A BIOKINETIC APPROACH TO THE PREVENTION AND REHABILITATION OF SHOULDER INJURIES

A BIOKINETIC APPROACH TO THE PREVENTION AND REHABILITATION OF SHOULDER INJURIES
University of Pretoria etd – Gouws, K (2006)
A BIOKINETIC APPROACH TO THE PREVENTION AND
REHABILITATION OF SHOULDER INJURIES
IN TENNIS PLAYERS
by
KARIEN GOUWS
submitted in partial fulfillment of the
requirements for the degree
DOCTOR PHILOSOPHIAE
in the
FACULTY OF HUMANITIES
(DEPARTMENT OF BIOKINETICS, SPORT AND LEISURE SCIENCES)
UNIVERSITY OF PRETORIA
NOVEMBER 2005
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DEDICATION
This dissertation is dedicated to my husband!
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ACKNOWLEDGEMENTS
I would like to thank all those people and institutions that helped me to
successfully complete this study. Thank you for your guidance by sharing your
knowledge, and all your loving care.
Prof. P.E. Krüger (Promotor): (Department Biokinetics, Sport and Leisure
Sciences, University of Pretoria). For his continuous guidance and support
throughout the study. I would also like to thank him for helping me through
situations where I was not able to travel to Pretoria. It was an honor to be his
student.
Wilmarie Visagie: For all the arrangements with the tennis players, help with the
testing and implementation of the training and rehabilitation programmes.
Sport Research Institute, University of Pretoria: For the help and support of
all my colleagues and Biokinetic Honours’ students (2003).
Subjects who participated in this study: For their time, co-operation and their
willingness to take part in this study.
South African Tennis Performance Centre: For making it possible to use their
tennis players in this study.
International Tennis Federation: For making it possible to use their tennis
players in this study.
Marlize Alexander: For her guidance and work done in the analysis of the
statistical data obtained.
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Charles Skeen: For taking the photographs.
Adèle Lubbe: For posing for the photographs.
Penny Botha: For proof reading the document.
Wynand Gouws: Without the continuous support of my husband and his
assistance with our children at home, it would have been impossible for me to
complete this study.
My Parents: My parents have always been there for me, to motivate and support
me in order to make my dreams come true.
Miriam: For all the extra hours spent in looking after the children.
Jesus Christ: His strength carried me through this study!
University of Pretoria etd – Gouws, K (2006)
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SYNOPSIS
TITLE
A
Biokinetic
Approach
to
the
Prevention
and
Rehabilitation of Shoulder Injuries in Tennis Players.
CANDIDATE
Karien Gouws
PROMOTOR
Prof. P.E. Krűger
DEGREE
DPhil (MBK) Biokinetics
Sports scientists and trainers generally agree that the multidimensional training in
tennis should start during early childhood in order to ultimately reach a
professional playing standard. Evidence suggests that motor skills, including
power, strength, agility, speed and explosive power, as well as mental strength
and a highly developed neuromuscular coordinating ability are strongly correlated
with the level of tournament performance. Turner & Dent (1996) found that 27%
of all tennis injuries in junior players occur in the shoulder region. The shoulder
girdle is prone to injury because of its ability to maximally accelerate and
decelerate the arm while the arm maintains it maintains precise control over the
racquet at ball contact.
The purpose of this study was to determine whether the occurrence of shoulder
injuries could be minimized in tennis players by following a specific exercise
programme, focusing on the shoulder girdle.
A total of 42 tennis players participated in this study. They were all aged between
14 and 18 years. Both males and females were used for the purpose of this
study. All the players were training at the SA Tennis Performance Centre and the
International Tennis Federation at the University of Pretoria. They were all elite
tennis players practising daily and scheduled for standard major tournaments
throughout the year.
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Each subject completed a questionnaire of his or her tennis and medical history.
The players were then divided into a control group and an experimental group.
Both groups completed a series of physical scientific tests, consisting of posture
analysis, body composition, flexibility, functional strength of the upper body; and
isokinetic power and endurance of the shoulder muscles.
These tests were executed every 3 months over a 9-month period and the results
of each battery of tests were used to adjust and upgrade the new programmes.
The experimental group did specific preventative shoulder exercises 5 times a
week in addition to their usual gymnasium programme twice a week, while the
control group followed a normal strengthening programme twice a week. A
medical doctor immediately evaluated any muscle stresses or pains throughout
the year. At the end of the year the data was compared to determine the
difference in injury occurrence between the two groups.
There was a significant difference (p<0.05) in the distribution of the lean body
mass with the Lean body mass at T1 being lower than the Lean body mass at T3
in the control group. In the experimental group the fat percentage showed a
significant decrease (p<0.05) from T1 to T3. The distribution of the muscle
percentage at T1 was significantly different (p<0.05) from the distribution of the
muscle percentage at T3 in the experimental group with the muscle percentage
at T1 being lower than the muscle percentage at T3.
There was a significant difference between the control and experimental group
for 1RM bench press (p<0.05) with the 1RM bench press measurements at T3
being lower for the control group than for the experimental group. Also, the 1RM
bench press at T1 was lower than the 1RM bench press at T3 in the
experimental group. The experimental group showed a significant increase from
T1 to T3, peaking at T3 with the 1RM bench press.
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Results of the tests done to determine isokinetic muscle strength showed that
a statistical significant correlation (p<0.05) was found with regard to the strength
of the internal rotators of the non-dominant shoulder at T3, with the
experimental group having a higher measurement than the control group. The
internal rotators and external rotators of both the dominant and non-dominant
shoulders were lower at T1 than at T3 in the experimental group (p<0.05). The
external rotators of the non-dominant shoulder at T1 were lower than the
external rotators of the non-dominant shoulder at T3 in the control group.
Results of the tests done to determine flexibility showed a statistically significant
difference with the internal rotators and external rotators of the dominant as
well as the non-dominant shoulders being lower at T1 than at T3 in the
experimental group. Also, the external rotators of the non-dominant shoulder of
the control group were lower at T1 than at T3.
Results of the tests done to determine posture showed that in the control group,
54.5% of the players had scoliosis at T1 as opposed to 40.9% at T3. In the
experimental group 55% had scoliosis at T1 compared to the 30% at T3. In the
experimental group, 55% of the players’ shoulder heights were not level at T1,
compared to 30% at T3. 63.6% of the control group’s non-dominant shoulders
were higher than the dominant shoulder at T1, compared to the 40.9% of
subjects at T3. Among the subjects in the experimental group, 50% had a higher
non-dominant shoulder and 5% a higher dominant shoulder at T1, compared to
25% and 5% respectively in the control group, at T3.
Results of the tests done to determine the occurrence of injuries, showed that the
subjects with no injuries in the control group stayed stable from T1 (54.5%) to
T2 (54.5%) whereafter it increased to 59.1% at T3. The experimental group
stayed stable from T1 (55.0%) to T2 (55.0%) where after it increased to 85% at
T3. In the control group the percentage grade 1 and 2 injuries was 13.6% at T1,
increasing to 18.2% at T2, and decreasing to 13.6% at T3. In the experimental
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group 15% of the subjects had grade 1 injuries at T1. This percentage increased
to 30% at T2 where after it decreased to 15% at T3 again. The percentage of
subjects with grade 2 injuries in the experimental group remained stable at
10.0% from T1 to T2. None of the subjects had grade 2 injuries at T3. In the
control group 9% had grade 3 injuries at T1, with none at T2 and T3. In the
experimental group the percentage of subjects with grade 3 injuries remained
stable at 5.0% from T1 to T2. None of the subjects had grade 3 injuries at T3. In
the control group 4.5% of subjects had grade 4 injuries at T1. This stayed more
or less stable at T2 (4.6%) and increased to 9.1% at T3. In the experimental
group 10.0% had grade 4 injuries at T1. None of the subjects had grade 4
injuries at either T2 or T3. In the control group 4.5% had grade 5 injuries at T1,
none had it at T2, and 4.5% had it at T3. In the experimental group none of the
subjects had grade 5 injuries at T1, T2 or T3. In the control group none of the
subjects had grade 6 injuries at T1 or T3. At T2, however, 4.6% had grade 6
injuries. In the experimental group 5.0% of the subjects had grade 6 injuries at
T1 and none had this type of injury at T2 or T3.
In conclusion, the results indicate that a specifically designed exercise
programme can help to diminish the risk of shoulder injuries in tennis players. It
can also improve bi-lateral muscle strength in opposing muscle groups which are
used in tennis.
KEY WORDS: Tennis, shoulder injuries, training programmes, rehabilitation
programmes, tennis strokes, biomechanics of tennis, elbow injuries, posture,
skoliosis, muscle strength.
________________________________________________________________
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SAMEVATTING
TITEL
‘n Biokinetiese benadering tot die voorkoming en
rehabilitasie van skouer beserings in tennisspelers.
KANDIDAAT
Karien Gouws
PROMOTOR
Prof. P.E. Krűger
GRAAD
DPhil (MBK) Biokinetika
Sportwetenskaplikes en afrigters stem saam dat multi-dimensionele afrigting in
tennis reeds tydens die vroeë kinderjare moet begin om sodoende ‘n
professionele standaard te bereik. Navorsing toon dat motorvaardighede soos
krag, ratsheid, spoed en plofkrag asook breinkrag en ‘n hoogs ontwikkelde
neuromuskulere koördinasie vermoë ‘n sterk ooreenkoms toon met prestasie in
toernooie. Turner & Dent (1996) het bevind dat 27% van alle tennisbeserings in
junior spelers in die skouerarea voorkom. Die skouergordel is baie vatbaar vir
beserings as gevolg van sy funksie om die arm maksimaal te versnel en spoed te
verminder terwyl die arm goeie beheer oor die raket uitoefen tydens balkontak.
Die doel van die eksperimentele studie was om vas te stel of skouerbeserings by
tennisspelers verminder kan word deur ‘n spesifieke oefenprogram te volg wat
fokus op die versterking van die skouergordel.
In die studie is daar van 42 tennisspelers gebruik gemaak. Al die spelers was
tussen 14 en 18 jaar oud. Beide seuns en dogters is gebruik vir die studie. Al die
spelers het geoefen by die “SA Tennis Performance Centre” en die
Internasionale Tennis Federasie by die Universiteit van Pretoria. Almal was elite
tennisspelers wat daagliks geoefen het en geskeduleer was vir sekere groot
toernooie deur die loop van die jaar.
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Elke proefpersoon het ‘n vraelys voltooi rakende sy of haar tennis- en mediese
geskiedenis. Daarna is die proefpersone in ‘n kontrole- en eksperimentele groep
verdeel. Beide die groepe het ‘n reeks sportwetenskaplike toetse voltooi,
bestaande uit postuur analise, liggaamsamestelling, soepelheid, funksionele krag
van die bolyf, en isokinetiese krag en uithouvermoë van die bolyf.
Die toetse is elke 3 maande oor ‘n tydperk van 9 maande uitgevoer. Die resultate
van elke reeks toetse is gebruik om die nuwe programme aan te pas. Die
eksperimentele groep het 5 maal per week spesifieke voorkomende skouer
oefeninge gedoen addisioneel tot hul gewone gimnasium program twee maal per
week. ‘n Mediese dokter het alle spierpyne en beserings onmiddellik geevalueer
reg deur die toetsperiode. Aan die einde van die toetsperiode is die data gebruik
om die voorkoms in beserings tussen die twee groepe te vergelyk.
Daar was ‘n beduidende verskil (p<0.05) in die verspreiding van vetvrye massa
met ‘n laer vetvrye massa by T1 (toets1) teenoor T3 (toets 3) in die kontrole
groep. Die vetpersentasie van die eksperimentele groep het ‘n beduidende
afname getoon vanaf T1 na T3 (p<0.05). Die verspreiding van spierpersentasie
was beduidend laer in die eksperimentele groep tydens T1 teenoor T3 (p<0.05).
Daar was ‘n beduidende verskil tussen die kontrole en die eksperimentele groep
se 1RM (Een Maksimale Repetisie) borsstootkrag waardes (p<0.05). Die 1RM
borsstootkrag van die kontrole groep was laer as die van die eksperimentele
groep tydens T3. Die eksperimentele groep het ‘n beduidende toename getoon
vanaf T1 tot T3 in 1RM borsstootkrag.
Die resultate van isokinetiese spierkrag dui op ‘n statisties beduidende
korrelasie (p<0.05) vir die krag van die interne rotators van die nie-dominante
skouer tydens T3, met die eksperimentele groep wat ‘n hoër waarde as die
kontrole groep behaal het. Die interne en eksterne rotators van beide die
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dominante and nie-dominante skouers was laer tydens T1 as T3 (p<0.05). Die
eksterne rotators van die kontrole groep was laer by T1 as by T3.
Die soepelheidstoetse het getoon dat die interne rotators en die eksterne
rotators van die dominante sowel as die nie-dominante skouers beduidend laer
was tydens T1 as T3 by die eksperimentele groep. By die kontrole groep was die
externe rotators van die nie-dominante skouer laer by T1 as by T3.
Die postuur analise dui daarop dat skoliose by 54.5% van die proefpersone in
die kontrole groep tydens T1 teenwoordig was teenoor 40.9% tydens T3. By die
eksperimentele groep het 55% skoliose gehad tydens T1 teenoor die 30%
tydens T3. In die eksperimentele groep was 55% van die proefpersone se
skouerhoogtes oneweredig in T1 teenoor die 30% in T3. In die kontrole groep
was 63.6% se nie-dominante skouer hoër as die dominante skouer tydens T1
teenoor 40.9% tydens T3. In die eksperimentele groep was 50% van die
proefpersone se nie-dominante skouer hoër en 5% se dominante skouer hoër
tydens T1, teenoor 25% en 5% respektiwilik tydens T3.
Die resultate van die voorkoms van beserings, dui dat die persentasie met geen
beserings in die kontrole groep konstant gebly het vanaf T1 (54.5%) tot T2
(toets 2) (54.5%) waarna dit toegeneem het tot 69.1% in T3. In die
eksperimentele groep het die geen beserings ook konstant gebly vanaf T1
(55%) na T2 (55%) waarna dit toegeneem het tot 85% in T3. In die kontrole
groep was die proefpersone met graad 1 en 2 beserings 13.6% in T1, dit het
toegeneem tot 18.2% in T2 en weer afgeneem tot 13.6% in T3. In die
eksperimentele groep het 15% van die proefpersone graad 1 beserings gehad
met T1, dit het toegeneem tot 30% met T2 en weer afgeneem tot 15% in T3. Die
graad 2 beserings van die eksperimentele groep het konstant gebly met 10%
tydens T1 en T2, met geen Graad 2 beserings tydens T3 nie. In die kontrole
groep was daar 9% graad 3 beserings tydens T1, en geen tydens T2 en T3 nie.
In die eksperimentele groep het die graad 3 beserings konstrant gebly met 5%
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vanaf T1 tot T2, met geen graad 3 beserings tydens T3 nie. In die kontrole groep
het 4.5% graad 4 beserings gehad tydens T1. Dit het min of meer konstant
gebly met 4.6% tydens T2 en gestyg tot 9.1% met T3. Die eksperimentele groep
het 10% graad 4 beserings gehad tydens T1, maar geen tydens T2 en T3 nie. In
die kontrole goep was daar 4.5% graad 5 beserings tydens T1, geen tydens T2
nie en weer 4.5% tydens T3. In die eksperimentele groep was daar geen graad 5
beserings tydens T1, T2 of T3 nie. In die kontrole groep was daar geen graad 6
beserings tydens T1 en T3 nie, maar 4.6% van die proefpersone het graad 6
beserings tydens T2 gehad. In die eksperimentele groep het 5% graad 6
beserings gehad met T1, maar geen tydens T2 en T3 nie.
Om saam te vat, die resultate dui daarop dat ‘n spesifiek ontwerpte
oefenprogram wel kan bydra om die risiko vir skouerbeserings te verminder. Dit
kan ook help om die bi-laterale spierkrag in antagonistiese spiergroepe, wat in
tennis gebruik word, te verbeter.
________________________________________________________________
SLEUTELWOORDE: Tennis, skouerbeserings, oefenprogramme, rehabilitasie
programme, tennis tegnieke, biomeganika van tennis, elmboogbeserings,
skoliose, spierkrag.
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TABLE OF CONTENTS
PAGE NO
TITLE PAGE……………………………………………………………………… i
DEDICATION…………………………………………………………………….. ii
ACKNOWLEDGEMENTS………………………………………………………. iii
SYNOPSIS………………………………………………………………………... v
SAMEVATTING………………………………………………………………….. ix
TABLE OF CONTENTS………………………………………………………… xiii
LIST OF FIGURES………………………………………………………………. xix
LIST OF TABLES………………………………………………………………... xxv
CHAPTER 1: THE PROBLEM
1.1 INTRODUCTION…………………………………………………………….. 1
1.2 PROBLEM SETTING……………………………………………………….. 4
1.3 RESEARCH HYPOTHESES..………………………………………………6
1.4 PURPOSE AND AIM OF THE STUDY…………………………………….6
1.4.1 Primary objectives
7
1.4.2 Secondary objectives
7
CHAPTER 2: LITERATURE REVIEW
2.1 THE HISTORY OF TENNIS…………………………………………………8
2.2
2.1.1
Ancient tennis
8
2.1.2
South Africa’s tennis history
11
ANATOMY OF THE SHOULDER……………………………………….12
2.2.1
Synovial Joints
13
2.2.1.1
General structure
13
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2.2.1.2
Bursae and tendon sheath
17
2.2.1.3
Factors influencing the stability of synovial joints
18
2.2.2
Structure of the shoulder (glenohumeral) joint
19
2.2.2.1
General structure
19
2.2.2.2
Ligaments
23
2.2.2.3
Tendons
24
2.3 MUSCLES AND MOVEMENTS OF THE SHOULDER GIRDLE……….26
2.3.1
Movements of the shoulder girdle
26
2.3.2
Movements of the shoulder joint
27
2.3.3
Scapulohumeral rhythm
28
2.3.4
Muscles of the shoulder
29
2.3.5
Muscle groups and surface anatomy
36
2.3.6
Prime muscles used in tennis
40
2.4 ANALYSIS OF THE SHOULDER IN TENNIS-SPECIFIC
MOVEMENTS……………………………………………………………… 44
2.4.1
The serve
44
2.4.2
Ground strokes
47
2.5 PHYSICAL DEMANDS OF TENNIS……………………………………… 49
2.5.1
Physiology of flexibility
50
2.5.1.1
Types of flexibility
51
2.5.1.2
Factors influencing flexibility
53
2.5.1.3
Areas that need flexibility training
54
2.5.1.4
Benefits of flexibility
58
2.5.2
Strength and endurance
59
2.5.2.1
Weight training
59
2.5.3
Body composition
63
2.5.3.1
Characteristics of female and male tennis players
64
a. Anthropometrical aspects
64
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b. Biological aspects
67
c. Developmental aspects
69
d. Psychological aspects
70
2.6 INJURIES IN TENNIS PLAYERS…………………………………………. 73
2.6.1
Causes of injuries in tennis players
73
2.6.2
Occurrence of tennis injuries
76
2.6.3
Prevention of shoulder injuries
78
2.6.3.1
Precautions in strengthening the rotator
cuff muscles
79
2.6.3.2
Sport-specific training programmes
79
2.6.4
Rehabilitation of the injured shoulder
80
2.6.4.1
Physical examination of the shoulder
81
2.6.4.2
Principles of functional rehabilitation
85
2.6.4.3
Guidelines for core-based functional rehabilitation
87
2.6.4.4
Phases of rehabilitation
88
2.7 TENNIS SPECIFIC SHOULDER EXERCISES………………………… 91
2.7.1
Rotator cuff programme
91
2.7.2
Additional tennis specific upper body exercises
97
2.7.3
Forearm and wrist programme
101
2.7.4
Plyometric medicine ball programme for the shoulders
106
2.8 POSTURAL DEVIATIONS …..……………………………………………. 107
2.8.1
Scoliosis
107
2.8.1.1
Incidence of scoliosis
108
2.8.1.2
Screening for scoliosis
109
2.8.1.3
Development of the scoliotic curvature
110
CHAPTER 3: METHODS AND PROCEDURES
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3.1 METHODS…………………………………………………………………… 112
3.1.1
Subjects
112
3.1.2
Testing Environment
115
3.1.3
Equipment
115
3.2 PROCEDURES……………………………………………………………… 118
3.2.1
The questionnaire
118
3.2.2
Sub-dividing of subjects into groups
119
3.2.3
Physical testing procedure
119
3.2.3.1
Postural analysis
119
3.2.3.2
Body composition
120
3.2.3.3
Flexibility
128
3.2.3.4
Functional strength
130
3.2.3.5
Isokinetic strength
130
3.3 RESEARCH DESIGN………………………………………………………. 135
3.4 STATISTICAL ANALYSIS…………………………………………………. 136
3.4.1 Statistical data analysis procedures
137
a. Descriptive statistics
137
b. Inferential statistics
137
c. The Mann-Whitney test
137
d. Wilcoxon signed rank test
137
e. Friedman’s rank test for correlated samples
138
CHAPTER 4: RESULTS AND DISCUSSION
4.1 BODY COMPOSITION…………………………………………………… 139
4.1.1
Results of the analysis of the comparison of measurements
taken at T1 and T3 of the same group across
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various variables
4.1.2
139
Results of the analysis of the comparison of the
same group Across various measurements at
different time intervals
141
4.2 MUSCLE STRENGTH AND ENDURANCE………………………………143
4.2.1
Results of the analysis of the comparison of the two
groups on various measurements
4.2.2
Results of the analysis of the comparison of measurements
Taken at T1 and T3 of the same group across variables
4.2.3
143
144
Results of the analysis of the comparison of the same group
across various measurements at different time intervals
147
4.3 ISOKINETIC MUSCLE STRENGTH……………………………………… 149
4.3.1
Results of the analysis of the comparison of the two groups
on various measurements
4.3.2
149
Results of the analysis of the comparison of measurements
taken at T1 and T3 of the same group across various
variables
150
4.4 FLEXIBILITY………………………………………………………………… 156
4.4.1
Results of the analysis of the comparison of measurements
taken at T1 and T3 of the same group across various
time intervals
156
4.5 POSTURAL MEASUREMENTS………………………………………… 159
4.5.1
Scoliosis
159
4.5.2
Shoulder height
161
4.5.3
CM Bend
163
4.5.4
Higher hip
164
4.5.5
Kiphosis
165
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4.5.6
Lordosis
166
4.6 GRADES OF INJURIES…………………………………………………… 168
a. No injuries
170
b. Grade1 and grade 2 injuries
172
c. Grade 3 injuries
172
d. Grade 4 injuries
172
e. Grade 5 injuries
173
f. Grade 6 injuries
174
CHAPTER 5: CONCLUSIONS AND RECOMMENDATIONS……………… 176
REFERENCES …………………………………………………………………….182
APPENDIXES………………………………………………………………………199
APPENDIX A: Tennis Research Project Questionnaire……………………….199
APPENDIX B: Postural analysis for tennis players……………………………..201
APPENDIX C: Testing proforma………………………………………………….203
APPENDIX D: Shoulder strengthening programme……………………………205
APPENDIX E: Additional tennis conditioning exercises……………………….206
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LIST OF FIGURES
FIGURE
PAGE
Figure 1: General structure of a synovial joint ...........................................16
Figure 2: Friction-reduction structures: Bursae and tendon
Sheaths .......................................................................................................17
Figure 3: Ball-and-socket joint: The shoulder ............................................20
Figure 4: Shoulder joint relationships .........................................................21
Figure 5: Posterior view of the right scapula ..............................................22
Figure 6: Muscles crossing the shoulder and elbow joints,
causing movement of the arm and the forearm ..........................................25
Figure 7: A posterior view of the scapula and the humerus
during abduction of the humerus. (a) scapulothoracic angle,
(b) glenohumeral angle ...............................................................................28
Figure 8: The trapezius (T) in action indicating the four heads ..................30
Figure 9: Representation of the action of the serratus anterior
and the lower fibers of the trapezius as a force couple ..............................33
Figure 10: Triplanar diagrammatic view of the shoulder ............................37
Figure 11: The primary muscles used during the tennis serve ……………40
Figure 12: The rotator cuff muscle .........................................................…43
Figure 13: Trunk and shoulder stretch .......................................................56
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Figure 14: Overhead stretch ......................................................................56
Figure 15: Scapular stretch ........................................................................57
Figure 16: Shoulder squeeze ....................................................................57
Figure 17: Forearm flexor stretch ..............................................................58
Figure 18: Forearm extensor stretch .........................................................58
Figure 19: Passive distraction test ............................................................84
Figure 20: Prone horizontal abduction ......................................................92
Figure 21: 90º-90º External shoulder rotation ...........................................93
Figure 22: Scaption (Empty Can) .............................................................94
Figure 23: External shoulder rotation with rubber tubing ..........................95
Figure 24: External shoulder rotation with abduction ................................96
Figure 25: Seated row ...............................................................................97
Figure 26: Wrist curls ................................................................................101
Figure 27: Wrist curls: Flexors ..................................................................102
Figure 28: Forearm supination ...................................................................104
Figure 29: Ulnar deviation ......................................................................…105
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Figure 30: Athletes screened for scoliosis ……………… …………………..110
Figure 31: Harpenden Anthropometer ........................................................115
Figure 32: Model D2391 Detecto Standing scale .......................................115
Figure 33: Equipment used for measuring body composition ……………...116
Figure 34: Back evaluation door .................................................................117
Figure 35: The Cybex Norm ........................................................................118
Figure 36: Postural analysis: The athlete standing in an erect position …..119
Figure 37: Shrober’s test was used to determine thoracic spine motion ….120
Figure 38: Height measurement using the Harpenden
Antrometer ................................................................................................…121
Figure 39: Body weight measurement using the Detecto
Standing Scale ....................................................................................…….122
Figure 40: Measuring the skinfold of the Triceps muscle with the
Skinfold Caliper ....................................................................................……123
Figure 41: Measuring the width of the humerus using a
Wide-Spreading Caliper ........................................................................……126
Figure 42: Measuring flexibility of the shoulder rotators:
(a) neutral position, (b) external rotation, and (c) internal rotation ...............128
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Figure 43: Measuring flexibility of the shoulder flexors and
extenders (a) neutral position, (b) shoulder extension, and
(c) shoulder flexion ..........................…………………………………………...129
Figure 44: Demonstrating the correct push-up position .......................……130
Figure 45: Isokinetic muscles strength of shoulder flexion
and extension measured on the Cybex Norm .......................................…...131
Figure 46: Isokinetic muscles strength of the (a) shoulder adductors,
and (b) shoulder abductors measured on the Cybex Norm .........................132
Figure 47: Isokinetic muscle strength of (a) shoulder internal
and (b) external rotation measured on the Cybex Norm ..............................133
Figure 48: Statistically significant difference within groups:
Body Composition (T1 and T3)..........................................................……...140
Figure 49: Statistically significant difference in Body
Composition between T1, T2 and and T3...........................................……...141
Figure 50: Statistically significant difference between groups:
Muscle strength and endurance ..........................................................…….144
Figure 51: Statistically significant difference within groups:
Isokinetic muscle strength (T1 and T3)...............................................……...145
Figure 52: Statistically significant difference for muscle
strength and endurance between T1, T2 and T3 .................................…….147
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Figure 53: Statistically significant difference for muscle
strength and Endurance between T1, T2 and T3 (continue) .............……...148
Figure 54: Statistically significant difference between groups:
Isokinetic muscle strength (T3)............................................................……..150
Figure 55: Statistically significant differences within groups:
Isokinetic muscle strength (T1 and T3)..............................................……...151
Figure 56: Statistically significant difference within groups:
Isokinetic muscle strength (continue) (T1 and T3)..............................……...152
Figure 57: Statistically significant difference within groups:
Flexibility (T1 and T3).........................................................................……...156
Figure 58: Percentage of players within each group with
Kifosys at T1 and T3 ...........................................................................……..166
Figure 59: Percentage of players with Lordosys in both
groups at T1 and T3 ...........................................................................……..167
Figure 60: Control group: Grades of shoulder injuries (T1, T2 and T3)
..169
Figure 61: Experimental group: Grades of shoulder injuries (T1 and T3) 170
Figure 62: Figure 4 hamstrings stretch ……………………………………….207
Figure 63: Hamstrings stretch …………………………………………………207
Figure 64: Hamstrings super stretch ………………………………………….208
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Figure 65: Stork quadriceps stretch …………………………………………..208
Figure 66: Prone quadriceps stretch ………………………………………….209
Figure 67: Groin stretch ………………………………………………………..209
Figure 68: Seated groin stretch ……………………………………………….210
Figure 69: Hip twist ……………………………………………………………..210
Figure 70: Piriformis stretch ……………………………………………………211
Figure 71: Iliotibial band stretch ……………………………………………...211
Figure 72: Calf stretch …………………………………………………………212
Figure 73: Knee to chest flex ………………………………………………….212
Figure 74: Double knee to chest ………………………………………………213
Figure 75: Spinal twist ………………………………………………………….213
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LIST OF TABLES
TABLE
PAGE
Table 1: Muscles acting on the shoulder girdle ....................................34
Table 2: Muscle acting on the shoulder joint .........................................35
Table 3: The differences in weight distribution between males
and females ........................................................................................…64
Table 4: The differences in bones and joints between male
and female ..........................................................................................…64
Table.5: The differences in muscles between males and females ....….66
Table 6: The differences in fat tissue between males and females ...….66
Table 7: The differences in the respiratory system between males
and females .........................................................................................…68
Table 8: The differences in the circulatory system between males
and females .........................................................................................…68
Table 9: Characteristics that highlights differences in development
between males and females ................................................................…69
Table 10: Specific characteristics of the female body: Anatomical
and functional differences in systems and organs of the body ............…70
Table 11: The differences in motivation and interest between
males and females ...............................................................................…71
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Table 12: The differences in psychological variables between
males and females .............................................................................……72
Table 13: Epidemiology of upper extremity overuse injuries in
tennis players .....................................................................................……77
Table 14:Subject data of all the tennis players taking part in
this study ............................................................................................……114
Table 15: Normative values of the shoulder internal and
external rotation peak torque (ft-lb.) ................................................……133
Table 16: Normative values of the shoulder flexion and
extension peak torque (ft-lb.) ...........................................................……..134
Table 17: Normative values of the shoulder abduction and
adduction peak torque (ft-lb.) ...........................................................……..134
Table 18: Frequency tables for scoliosis for the control and
experimental groups for T1 ................................................................……..160
Table19: Frequency tables for scoliosis for the control and
experimental groups for T3 ...............................................................………160
Table 20: Frequency tables for the control and experimental
groups for shoulder height at T1 .......................................................………161
Table 21: Frequency tables for the control and experimental
groups for shoulder height at T3 .......................................................………162
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Table 22: Cross-tabulation of CM Bend at T1 with CM Bend
at T3 for both the control and experimental groups ..........................………163
Table 23: Frequency table for the control and experimental
groups for hip height at T1 ..............................................................……….164
Table 24: Frequency tables for the control and experimental
groups for hip height at T3 ..............................................................……….164
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1
A BIOKINETIC APPROACH TO
THE PREVENTION AND REHABILITATION
OF SHOULDER INJURIES
IN TENNIS PLAYERS
CHAPTER 1
THE PROBLEM
1.1 INTRODUCTION
Tennis is the widest played of all racquet sports in the world. Several million
people play tennis on a regular basis, socially and competitively. Of these people
playing tennis, 5000 to 8000 play in tournaments sanctioned by the United States
Tennis Association, and approximately 800 play tennis professionally (Fu &
Stone, 1994). The inherent qualities of modern tennis, which had its beginning on
24th of February 1874, have long ensured its popularity with participants and also
with spectators. From its very beginning, the appeal of the game has grown
steadily, spreading from country to country, reaching its present status as a preeminent international sport (Elliott et al., 1989; Cox & Applewhaite, 1990). The
evolution of major events, such as the Davis Cup, which was inaugurated in
1900, Wimbledon which is played in London, the United States Open
Championships at Forest Hills and the French Open Championships at Roland
Garros has served to cement the competitive game of tennis and stimulate
international appeal (Cox & Applewhaite, 1990).
Tennis is a social and enjoyable sport, a sport of ‘the upper class’, a well-loved
sport that everyone can play, regardless of age. It provides exercise and
recreation simultaneously (Ellwanger, 1973, Copley, 1975, Elliot et al., 1989;
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2
Konig et al., 2001). It is a safe, outdoor sport that improves mental and physical
health. It is an international sport that can be played throughout the year (Cillie,
1966; Ellwanger, 1973, Copley, 1975; Konig et al., 2001). King Gustaaf of
Sweden played tennis as Mr. G until the age of 84. Individual sports has the
advantage of not having to struggle to get a team together in order to play (Cillie,
1966). The most important gymnastic movements are found in tennis. This
includes bending of the body, turning, stretching, strengthening of the stomach,
arm and leg muscles (Ellwanger, 1973; Gokeler et al., 2001).
Specialization, which is the result of man’s continual striving for improvement and
development, has permeated almost every aspect of today’s modern society.
The motorcar, television and computer are all tangible evidence of concentrated
work and research in a technical field. In the field of sport, specialization has
resulted in feats of physical performance, which a few years ago were regarded
as totally impossible (Copley, 1975; Gokeler et al., 2001; Konig et al., 2001).
According to Copley (1975) sport specialization generally involves work and
scientific research in aspects such as equipment, training and conditioning,
coaching, teaching and administration. Intensive literature surveys and numerous
discussions with leading players and authorities have indicated that research in
tennis compared with other sports has been grossly neglected in respect of
training, conditioning, coaching and teaching of players (Fu & Stone, 1994;
Kraemer et al., 2003). Efforts have only recently been made to understand the
sport science of tennis. However, since 1990, great strides have been made in
understanding the biomechanics, physiology, psychology, and sports medicine of
tennis. This was done largely through research funded by the U.S. Tennis
Association (Kraemer et al., 2003). Based on this information it is possible to
develop programmes for better identification of injuries, preventative conditioning
of players and also for better skill acquisition (Fu & Stone, 1994). There are
basically two types of physical workout programmes: body- building programmes
that make you look great and sport-conditioning programmes that make you
play great. Although it is true that a body- building programme will help to some
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3
extent to prevent injuries, it is definitely not the best way to condition a tennis
player. Bulky muscles may restrict ones flexibility and slow the player down,
which will hinder performance (Chu, 1995; Gokeler et al., 2001; Kraemer et al.,
2003). It is therefore very important to develop a tennis specific conditioning
programme.
At the competitive level, junior players are required to have sound stroke
production and good physical fitness, combined with the psychological
characteristics that enable both successful performance and normal socialization
with children of their own age (Elloitt et al., 1989; Montalvan et al., 2002). A
growth spurt, which is a period of rapid growth, occur during the ages of 10 to 14
years in females and 13 to 17 years in males. With the increased interest in
organized sport, it is important to take these growth spurts into consideration
when designing training programmes (Fu & Stone, 1994; Kraemer et al., 2003).
The shoulder is paramount importance for all competitive tennis players
(Plancher et al., 1995). Turner & Dent (1996) found that 27% of all tennis injuries
in junior players occur in the shoulder region. The shoulder girdle is prone to
injuries because of its function to maximally accelerate and decelerate the arm
while it maintains precise control over the racquet at ball contact (Hagerman &
Lehman, 1988; Carson, 1989; Plancher et al., 1995; Kraemer et al., 2003).
According to unpublished data that was collected from three elite male tennis
players at the University of Kentucky Bio-dynamics Laboratory, the indication
was that the peak velocity of a tennis racquet in the serve ranged from 99 to 115
km/h. This corresponds with ball velocities of 133 to 200 km/h (Thompson, 1986).
The specific muscles groups that are prone to injuries vary from person to
person. If we take a look at Tod Martin and Michael Chang, they were both topranked players. Tod Martin, with a height of 1.95m, uses his big serve and large
wingspan at the net, placing his shoulder muscles under tremendous tension.
Michael Chang on the other hand, with a height of 1.7m, plays a baseline game,
running down basically every shot, using agility and maximum leg power. Apart
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4
from their different training programmes, they do have one thing in common and
that is their excellent training habits and physical fitness level (Roetert &
Ellenbecker, 1998).
The complex interaction between muscle fatigue, eccentric overload and primary
instability with secondary impingement can lead to disability in tennis players
(Plancher et al. 1995). Previous research done by Chard & Lachman (1998)
indicated that 2,3 injuries occurred per player per 1000 hours. Of these injuries,
47,3% occurred during training sessions, 25,5% during matches and 27,2% while
participating in other recreational activities. Sixty seven percent of these injuries
were due to overuse injuries. By exploring and understanding all these aspects of
tennis dynamics, a shoulder rehabilitation and conditioning program can be
developed that will diminish disability and enhance performance in a tennis
player.
1.2
PROBLEM SETTING
Sport scientists and trainers generally agree that the multidimensional training in
tennis should start in early childhood in order to reach a professional playing
standard (Muller et al., 2000). A thorough knowledge of the physiological and
patho-physiological response to training and match play is essential for the
supervision of training in complex sports, such as tennis. Evidence suggests that
motor skills including power, strength, agility, speed and explosive power as well
as mental strength and a highly developed neuromuscular co-ordinating ability
are strongly correlated with the level of tournament performance (Konig et al.,
2001). Therefore, improvements of these aspects are indispensable for reaching
the international performance level (Muller et al., 2000; Konig et al., 2001). Thus,
if an athlete is not in good physical condition, the other essential characteristics
in tennis, such as technique, co-ordination, concentration and tactics cannot be
brought into play in long matches, because premature fatigue will impair virtually
all tennis-specific skills (Konig et al., 2001).
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5
More and more players are becoming serious about their tennis, taking it to much
higher levels than recreational play. Participating in competitive tennis was much
simpler in the 1950’s and 1960’s (Roetert & Ellenbecker, 1998). In the future, the
science of training will be called upon for the optimization of training methods in
high-performance sport (Muller et al., 2000).
Tennis is a combination of endurance and power. In every match training session
there are between 300 and 500 bursts of energy, each requiring both power and
co-ordination of movement (Turner & Dent, 1996).
The modern tennis game:
•
encourages the use of maximum effort in order to increase ball speed off the
racquet which results in larger forces being absorbed by the body; and
•
involves young players that participate in high intensity training pragrammes
resulting in the growing body being more susceptible to damage (Turner &
Dent, 1996).
Both of these above-mentioned features in tennis necessitate that tennis injuries,
the warning signs of injuries, as well as their treatment need to be investigated
carefully. Importantly, the coaches and trainers should know what to do in order
to reduce the risk of injury (Turner & Dent, 1996; Konig et al., 2001).
According to Ellenbecker (1995) it is important to formalize a comprehensive
rehabilitation programme that focuses on the upper extremity kinetic chain,
regardless of the specific location of the upper extremity injury. In this way the
programme will serve to restore normalized joint arthrokinematics and enables a
full return to repetitive musculoskeletal demands of tennis.
This leads to the question whether or not, and to what extent, a tennis specific
exercise programme will minimize the occurrence of shoulder injuries in tennis
players. Also, once the tennis player got injured, will a specifically designed
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rehabilitation programme enhance the recovery period and prevent that injury
from re-occurring?
1.3
RESEARCH HYPOTHESES
The following hypotheses are related to the purpose of this study:
1. A specifically designed exercise programme can help to diminish disability in
tennis players due to shoulder injuries; and
2. A specifically designed tennis programme for the shoulder can improve bilateral muscle strength in the opposing muscle groups, used in tennis.
1.4
PURPOSE AND AIM OF THE STUDY
The purpose of this study is to determine whether, by following a specific
exercise programme, focusing on the shoulder girdle, the occurrence of shoulder
injuries in tennis players can be minimized. According to Muller & Wachter (1989)
and Schmidt-Wiethoff et al. (2003), athletic capacity will most probably improve
by increasing the quality of training rather than the quantity of training. In this
study we want to determine this improvement by using special technique and
sport-specific tests. By building up the athletic capacity, an athlete will be kept
injury-free and into play for a longer period of time. It has been proved by
numerous studies that the training for general conditioning, valid for all forms of
sport, leads to improvement of particular physical parameters. However, this kind
of training hardly succeeds in increasing competitive capacity. On the other hand,
the use of technique-specific methods of training, parallel with general
conditioning training, can lead to considerable performance improvements
(Hakkinen & Komi, 1985; Rutherford & Jones; 1986; Werschoshanskij, 1988;
Sale, 1993; Muller et al., 2000).
In order to develop a programme that will help the athlete to improve his
performance, the following aspects need to be investigated.
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7
1.4.1 Primary objectives:
a. To determine whether a specialized exercise programme, focusing on tennis
dynamics, will minimize the occurrence of shoulder injuries in junior tennis
players.
b. To determine whether a specifically designed tennis programme for the
shoulder, can improve bi-lateral muscle strength in the opposing muscle
groups, used in tennis.
1.4.2 Secondary objectives:
a. To determine the bio-mechanical working of the shoulder girdle in the various
tennis strokes .
b. To determine the influence of specific exercises on the functioning of these
muscles.
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CHAPTER 2
LITERATURE REVIEW
This section of the review covers the anatomy and physiology of the shoulder, its
role and importance in tennis and how the shoulder is affected by normal tennis
biomechanics. In this epidemiological study, it is important to understand all
those factors that could influence the output of the research.
2.1 THE HISTORY OF TENNIS
2.1.1 Ancient Tennis:
Tennis is one of the few games that was not thought up by the English. Tennis
began at the French Court and was played in a walled court. The balls were not
only hit over the net, but also against the walls (Lawn Tennis, 1973). According to
mosaics, statues and learned writings, the ancient Romans and Greeks also
played a form of tennis (Brace, 1984). The medieval French also slapped a ball
back and forth with their hands and called this game “jeu de paume”. King Henry
VIII rose at five in the morning to play tennis in an enclosed court at Hampton
Court Palace (Brace, 1984). It started out as Real or Royal Tennis, much
favoured by the Court and therefore sometimes known as Court Tennis (Lawn
Tennis, 1973). He had his own professional, Anthony Ansley, who had to supply
the balls and the racquets and who also kept the score. The game, which King
Hal played with great “gusto”, is known as real tennis. This real tennis is still
played by a small group of loyal people using the same curiously shaped indoor
court, lopsided rackets, and balls made of compressed cloth covered by handstitched felt. Real tennis became a popular game for clerics in the cloisters of
French monasteries. Until this day it retains its original French names (“dedans”,
“grille”, and “tambour”) (Brace, 1984). Eventually, around 1870, the game was
adapted to be played mainly outdoors on grass, and this was the beginning of
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Lawn Tennis (Lawn Tennis, 1973). Lawn tennis, the outdoor version of this
esoteric pursuit, only became prominent in the 19th century. The man described
as the inventor was Major Walter Clopton Wingfield (Tingay, 1973; Brace, 1984).
Major Wingfield was a retired Army officer and a member of Gentleman-at-Arms
at the court of Queen Victoria (Wind, 1979; Brace, 1984). He was resident at
Rhysnant Hall and attended a house party at Nantclwyd Hall, where the game
was first played in 1873 (Tingay, 1973; Brace, 1984). He published a book of
rules in December 1873 and then two months later he applied for a patent on “A
New and Portable Court for Playing the Ancient Game of Tennis”. Major
Wingfield called his game Sphairristike. This Greek word was soon abbreviated
to “Sticky” and then eventually it was abandoned in favour of “Lawn Tennis”
which was easier to pronounce and to remember (Brace, 1984). The game came
in a painted box that contained poles, pegs and netting to create a court, also
four tennis bats, a supply of hollow India rubber balls, a mallet and brush and a
book with the rules of the game. It cost five guineas and was designed to be
played on grass, ideally on frosty days when the best of shooting was over and
the ground was too hard for hunting (Tingay, 1973; Wind, 1979; Brace, 1984).
There is also firm evidence that Lawn Tennis was played at Edgbaston in 1858
and then subsequently at the Manor House Hotel, Leamington, where a plaque
states clearly: ‘On this lawn in 1872 the first lawn tennis club in the world was
founded” (Tingay, 1973; Brace, 1984). Major Harry Gem and Mr. J.B. Perera
were the initiators here. Their court was rectangular, unlike the hourglass shape
of Major Wingfield’s court. The rules of their game was compiled by Major Harry
Gem and it is therefore fairer to link the two Majors – Gem and Wingfield – in
awarding the credit for launching Lawn Tennis (Tingay, 1973; Brace, 1984). The
tennis and racket sub-committee of the Marylebourne Cricket Club (MCC) started
to revise the rules of real tennis and new rules were published on the 3rd of
March 1875. A significant innovation was that the serve should be delivered with
one foot behind the baseline and aimed alternately into the opposite square of
the court between the net and the service line. The score went up to 15 points
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10
with deuce-advantage played at 14/14 (Tingay, 1973). This was a very important
step towards uniformity in tennis, but a far more momentous development
occurred in 1877. The All-England Croquet Club decided to stage a tournament
at its grounds at Worple Road, Wimbledon (Brace, 1984). The goal was to raise
money for the repair of a pony-roller (Brace, 1984). The pony-roller is a roller that
was designed to be drawn by a horse or a pony. It stands behind the stop netting
on the north side of Centre Court at Wimbledon. The roller was so wide, that
having been used to level the immaculate turf when the new All England Club
was built in 1922, there is now no way of removing it from of the arena, for all the
exits are too narrow (Tingay, 1973). A Committee consisting of Henry Jones,
Julian Marshall and C.H. Heathcote was entrusted to finalize the rules of the
MCC, and came up with the rules, which have held to the present day. They
agreed that the court should be rectangular, 23,8 meters long and 8,2 meters
wide, and that tennis scoring should be used. They laid the foundations of Lawn
Tennis, as we know it today. This major event was the world’s first Lawn Tennis
Tournament and the birth of Wimbledon, which remains the centerpiece of the
game (Lawn Tennis, 1973; Tingay, 1973; Brace, 1984). Major Wingfield was
awarded the M.V.O. in 1902 and died in April 1912 in his eighties (Tingay, 1973).
An American, Mary Outerbridge, succumbed to the game in Bermuda where the
British garrison played the game and constructed a court on Staten Island, New
York, in 1874. In America the game was called “Court Tennis”. Thus Lawn
Tennis has crossed the Atlantic Ocean (Brace, 1984). In 1881, eight years after
Major Walter Lopton Wingfield had advised the game of Lawn Tennis, this
country set up its own governing body. This was called the United States
National Lawn Tennis Association, with thirty-four clubs affiliated with it (Tingay,
1973; Wind, 1979). A few years ago a startling communiqué was released from
the U.S.L.T.A.’s main office that in the future, the U.S.L.T.A. would become the
U.S.T.A. (United States Tennis Association). This made sense, for their national
championships were no longer played on grass, but on a synthetic clay-like
surface called Har-Tru (Wind, 1979).
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11
The tennis scoring terms ‘fifteen’ for one point, ‘thirty’ for two points and ‘forty’ for
three points puzzles the minds. This scoring came about by recording the
progress of rallies (called ‘rest’ in real tennis) on a clock alongside the court.
Once the player had won one point his pointer moved to one quarter, the fifteenth
minute division. Winning the second point would take him to the next quarter, to
thirty minutes. On the third point the marker moved to the three-quarter, to fortyfive minutes. It was only during the eighteenth century that the convention arose
to abbreviate ‘forty-five’ to ‘forty’. Once the full cycle was completed, it marked a
game. This contest was set in order to comprise so many games (Tingay, 1973).
2.1.2 South Africa’s Tennis History:
It all began in Port Elizabeth, as did many other sports in South Africa. The first
cricket test in South Africa was played in Port Elizabeth, so was the first
international rugby test, and so, in 1891, was the inaugural South African tennis
championship tournament also played in Port Elizabeth (Eldridge, 1978). It was
written in 1897 that the inaugural South African Championships were ‘the
forerunner of many enjoyable and first-class matches’ (Eldridge, 1978; Van der
Merwe, 1992).
South African championships can be divided into four eras:
•
First era: This was the time between 1891 and the Anglo-Boer War when
the
Port
Elizabeth
Lawn
Tennis
Club
instituted
the
national
championships. This open tournament at Port Elizabeth extended over
four days and it was the event of the year for the whole of South Africa;
•
Second era: This era followed the formation of the South African Lawn
Tennis Union in 1903. This tournament started to circulate between
Johannesburg, Cape Town, Durban, Port Elizabeth, East London,
Pretoria, Bloemfontein and Kimberley;
•
Third era: This period started in 1931 when Ellis Park, Johannesburg, was
made the official, permanent venue for this event; and
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12
•
Fourth era: This stage was launched in 1966 when SALTU started to
promote this tournament internationally.
(Grace, 1975; Eldridge, 1978; Van der Merwe, 1992)
Today, tennis is still going strong in South Africa with S.A.T.A (South African
Tennis Association) leading the way.
2.2
ANATOMY OF THE SHOULDER
According to Marieb (1995) joints are the weakest parts of the whole skeleton.
Their two basic functions are to hold the skeleton together and to provide mobility
(Hay & Reid, 1999; Martini et al., 2001). Their specific structure enables the joints
to resist crushing, tearing and various forces that could force them out of
alignment (Marieb, 1995; Roetert, 2003).
Structurally, joints can be classified as:
a. Fibrous joints:
These bones are joined by fibrous tissue with no joint cavity present. There are
three types of fibrous joints: sutures (found in the cranial bones in the skull),
syndesmoses (for example the interosseous membrane connecting the radius
and ulna along their length) and gomphoses (the articulation of a tooth) (Marieb,
1995; Martini et al., 2001; Roetert, 2003).
b. Cartilaginous joints:
Cartilage unites the articulating bones in cartilaginous joints. There are two types
of cartilaginous joints:
•
Synchondroses: This is found in the epiphyseal plates connecting the
diaphysis and epiphysis regions in long bones; and
•
Symphyses: Found in the intervertebral joints and the pubic symphysis
of the pelvis (Marieb, 1995; Hay & Reid, 1999; Martini et al., 2001).
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13
c. Synovial joints:
This is where the articulating bones are separated by a fluid-containing joint
cavity, which permits substantial freedom of movement. All the joints of the limbs
fall into this category (Marieb, 1995; Martini et al.2001).
Functionally, joints can be classified as:
a. Synarthoses: Immovable joints, which are mainly restricted to the axial
skeleton;
b. Amphiarthoses: Slightly movable joints, which are also mainly restricted to
the axial skeleton ; and
c. Diarthoses: Freely movable joints which predominate in the limbs (Marieb,
1995; Hay & Reid, 1999).
Functionally and structurally the shoulder is a diarthoses, synovial joint (Marieb,
1995).
2.2.1 Synovial Joints:
2.2.1.1
General structure:
As mentioned earlier, synovial joints are articulating bones separated by a fluidcontaining joint cavity, which allows freedom of motion (Marieb, 1995; Martini et
al., 2001). Typically, these joints have five distinguishing features (Figure 1):
i.
Articular cartilage:
Hyaline, which is a glassy-smooth articular cartilage, covers the opposing bone
surfaces. These spongy cushions absorb compression placed on the joint, and it
keeps the bone ends from getting crushed (Marieb, 1995; Martini et al., 2001).
University of Pretoria etd – Gouws, K (2006)
14
ii.
Joint cavity:
The joint cavity is filled with synovial fluid and is thus more of a potential space
rather than a real one (Marieb, 1995; Martini et al., 2001).
iii.
Articular capsule:
A double-layered articular capsule encloses the joint cavity. The external layer is
a strong and flexible fibrous capsule that is continuous with the periostea of the
articulating bones (Marieb, 1995; Martini et al., 2001).
iv.
Synovial membrane:
This membrane is composed of loose connective tissue. It lines the fibrous
capsule internally and covers all the internal joint surfaces that are not hyaline
cartilage (Marieb, 1995; Martini et al., 2001).
v.
Synovial fluid:
All free spaces within the joint capsule are filled up by a small amount of slippery
synovial fluid. This fluid is largely derived by filtration from the blood that flows
through the capillaries in the synovial membrane (Hay & Reid, 1999). Due to its
content of hyaluronic acid secreted by the cells of the synovial membrane,
synovial fluid has a viscous, egg white consistency. During joint activity the fluid
warms and becomes thinner and less viscous (Marieb, 1995). Synovial fluid is
also found within the articular cartilage and it provides a slippery, weight bearing
film that reduces friction between the cartilages. Weeping lubrication is a
mechanism that squeezes synovial fluid out and into the cartilage during
movements, lubricating their free surfaces and nourishing their cells. This
synovial fluid is forced from the cartilage every time a joint is compressed. As the
pressure on the joint is relieved, the fluid seeps back into the articular cartilage,
ready to be squeezed out the next time the joint is under pressure (Figure 1)
(Marieb, 1995; Hay & Reid, 1999; Martini et al., 2001; Roetert, 2003).
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Some synovial joints are reinforced and strengthened by ligaments. Most often,
the ligaments are intrinsic (capsular) and are thickened parts of the fibrous
capsule. In some other joints, the ligaments remain distinct and are found either
outside the capsule (extra- capsular) or deep in it (intra- capsular) (Hay & Reid,
1999).
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(b)
(b)
Figure 1: General structure of a synovial joint. (a) The articulating bone ends are
covered with articular cartilage and they are enclosed within an articular capsule.
The fibrous capsule, the exterior portion of the articular capsule, is continuous
with the periostea of the bones. Internally, the fibrous capsule is lined with very
smooth synovial membrane that secretes the synovial fluid. Ligaments typically
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17
reinforce these joints. (b) Scanning electron micrograph of the synovial
membrane of a knee joint (Marieb, 1995).
2.2.1.2
Bursa and tendon sheath:
Bursae and tendons are not strictly part of synovial membranes, but are often
found closely associated with them (Figure 2) (Marieb, 1995).
Figure 2: Friction-reduction structures: Bursae and tendon sheaths. (a). Frontal
section through the right shoulder joint indicating the sac-like bursae and the
tendon sheath around a muscle tendon. (b) An enlargement of part (a), indicating
the manner in which a bursae eliminates friction where a tendon is liable to rub
against a bone. The synovial fluid inside the bursae acts as a lubricant that
allows the walls to slide easily across each other. (c) An enlarged threedimensional view of the tendon sheath wrapped around the tendon of the biceps
brachii muscle (Marieb, 1995).
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Bursae, meaning “purse” in Latin, are flattened fibrous sacs lined with synovial
membrane and containing a thin film of synovial fluid (Martini et al., 2001;
Roetert, 2003). They are usually present in sites where ligaments, muscles, skin
or muscle tendons lie over and rub against a bone (Marieb, 1995; Hay & Reid,
1999). Many people have never heard of a bursa, but most people are familiar
with the word “bunion”. A Bunion is an enlarged bursa at the base of the big toe
that becomes swollen up due to rubbing against a tight or poorly fitting shoe
(Martini et al, 2001).
A tendon sheath is an elongated bursa that wraps completely around a tendon
where it is subjected to friction (Marieb, 1995; Hay & Reid, 1999).
2.2.1.3
Factors influencing the stability of synovial joints:
Joints are consistently stretching and compressing, therefore they must be
stabilized in order not to dislocate (Marieb, 1995; Roetert, 2003). The stability of
a synovial joint depends mainly on the following three factors:
i.
Articular surface:
The articular surface determines the movements that are possible at a specific
joint, but they play a minimal role in joint stability. Many joints have shallow
sockets that contribute little to joint stability. Other surfaces, for example the hip
joint, are large and fit snugly together, therefore improving stability (Marieb, 1995;
Martini et al., 2001; Montalvan et al., 2002).
ii.
Ligaments:
Ligaments of synovial joints unite the bones, direct movement and prevent
excessive and undesirable movement. The more ligaments around the joint, the
stronger it is (Martini et al., 2001). Although, when the other stabilizing factors are
inadequate, tension is placed on the ligaments, causing them to stretch. A
stretched ligament stays stretched, and can only be stretched by 6% of its
original length before in snaps (Marieb, 1995). Where ligaments are the major
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means of bracing a joint, the joint is not very stable (Marieb, 1995; Hay & Reid,
1999).
iii.
Muscle tone:
Muscle tone can be defined as low levels of contractile activity in relaxed
muscles, and helps to keep the muscles healthy and ready to react to stimulation
(Marieb, 1995; Martini et al., 2001; Roetert, 2003). In most joints, the muscle
tendons that cross the joint are the most important stabilizing factor and these
tendons are kept taut at all times by the tone of their muscles. This muscle tone
is extremely important in reinforcing the shoulder and knee joints as well as the
arches of the foot (Marieb, 1995, Hay & Reid, 1999; Martini et al., 2001).
2.2.2 STRUCTURE OF THE SHOULDER (glenohumeral) JOINT:
2.2.2.1
General structure:
The upper extremity is similar to the lower extremity in that they are both
connected to the trunk via a bony ring, or girdle (Hamill & Knutzen, 1995). The
shoulder joint is a synovial joint where the articulating bones are separated by a
fluid-containing joint cavity. The glenohumeral joint is the most freely moving
diarthoses in the body (Marieb, 1995). Two clavicles and two scapulae form the
shoulder girdle. The upper extremity connects to the trunk via the sternum, and
the shoulder forms an incomplete ring due the fact that the scapulae do not make
contact with each other in the back. This allows independent motion of the right
and left arms. In contrast, the lower extremity connects to the trunk via the
sacrum. This forms a complete ring with the pelvic girdle, since both sides of the
pelvis are connected to each other, both anteriorly and posteriorly (Hamill &
Knutzen, 1995, Hay & Reid, 1999; Roetert, 2003). The shoulder girdle has
additional skeletal attachments on the lateral sides of the body, with the head of
the humerus of the arm. It has to support the limbs, which increases its insecurity
further (Hay & Reid, 1999).
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Where the function of the lower extremity involves mainly weight bearing,
ambulation, posture and gross motor activities, the upper extremity participates in
activities requiring skills in manipulation, dexterity, striking, catching, and fine
motor abilities. Therefore, the shoulder is the most mobile extremity (Hamill &
Knutzen, 1995). The shoulder is a ball-and-socket joint, formed by the small,
shallow, pear-shaped glenoid cavity of the scapula and the head of the humerus
(Figure 3) (Marieb, 1995). In ball-and-socket joints, the hemispherical or
spherical head of one bone articulates with the concave socket of another bone.
These joints are multi-axial with universal movement in all axes and planes
(Figure 4) (Marieb, 1995; Hay & Reid, 1999).
Figure 3: Ball-and-socket joint: The shoulder (Marieb, 1995).
In the shoulder, the glenoid cavity is slightly deepened by the glenoid labrum,
which is a rim of fibro- cartilage, but it is only about one-third of the size of the
humeral head and contributes little to joint stability. There is a thin articular
capsule that encloses the joint cavity from the margin of the glenoid cavity to the
anatomical neck of the humerus. It is remarkably loose, contributing to the joint’s
freedom of movement (Marieb, 1995).
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Figure 4: Shoulder joint relationships. (a) An anterior view of the shoulder joint
(superficial aspect) illustrating some of the reinforcing ligaments, associated
muscles and bursae. (b) The right shoulder joint, cut open and viewed from a
lateral aspect where the humerus has been removed. (c) Anterior view of the
interior of the shoulder joint: A photograph (Marieb, 1995).
a.
The Scapula:
The scapula is a flat bone that is roughly triangular in shape with a medial, lateral
and superior border (Hey & Reid, 1999). It consists of three angles that are
superior, lateral and inferior. The costal surface that is closer to the surface of the
scapula is slightly concave in order to correspond with the shape of the rib cage
(Hamill & Knutzen, 1995; Martini et al., 2001). The dorsal surface has a
prominent ridge, which forms the spine of the scapula. This ridge extends
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22
laterally and ends in the acromion process, the point at which the clavicle
articulates. The glenoid fossa is a shallow concave articular surface inferior to the
acromion and it articulates with the head of the humerus. The coracoid process
projects forward under the clavicle and toward the head of the humerus all the
way from the superior border medial to the glenoid fossa (Figure 5) (Hay & Reid,
1999).
Figure 5: Posterior view of the right scapula (Hay & Reid, 1999).
b.
The Clavicle:
The clavicle has the appearance of an elongated “S” and it articulates with the
acromion process of the scapula on the lateral side and on the medial side with
the sternum. The medial half of the bone is anteriorly convex and the lateral side
is concave (Hay & Reid, 1999; Roetert, 2003).
c.
Joints of the Shoulder Girdle:
The shoulder girdle consists of two joints, which on each lateral side has a
glenoid fossa for articulation with the head of the humerus:
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i)
The Sternoclavicular Joint:
This joint is a synovial joint between the medial end of the clavicle and the
superior lateral corner of the manubrium of the sternum and the cartilage of the
first rib. A fibrous capsule covers the articulation and provides strength to the
joint by an:
•
anterior and posterior sternoclavicular ligament;
•
interclavicular ligament; and a
•
costoclavicular ligament (Marieb, 1995; Hay & Reid, 1999).
The sternoclavicular joint is a very strong joint and dislocation is uncommon. If
the acromion of the scapula is struck or when a force is transmitted from an
outstretched arm when the hand strikes the ground on falling, it is likely that the
clavicle may break, but the joint will rarely dislocate (Hay & Reid, 1999; Martini et
al., 2001).
ii)
The Acromioclavicular Joint:
The acromioclavicular joint, which is also an arthrodial joint, forms the union
between the lateral end of the clavicle and the acromion process of the scapula.
The superior and the inferior acromioclavicular ligaments aids in supporting the
joint (Marieb, 1995; Hay & Reid, 1999). The coracoclavicular ligament, which is
not part of the joint, helps to maintain the integrity of the joint. Dislocation of this
joint is common in contact sports when the athlete falls on his shoulder and this
condition is often incorrectly referred to as a “shoulder separation” (Hamill &
Knutzen, 1995; Hay & Reid, 1999; Martini et al., 2001).
2.2.2.2
Ligaments:
There are three ligaments reinforcing the shoulder joint, located primarily on its
anterior aspect:
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i)
Coracohumeral ligament:
This ligament extends from the coracoid process of the scapula to the greater
tubercle of the humerus. It provides the only strong thickening of the capsule and
it helps to support the weight coming from the upper limb (Marieb, 1995; Martini
et al., 2001).
ii)
Glenohumeral ligament:
There are three glenohumeral ligaments, which strengthen the front of the
capsule. They are very weak and in some cases may even be absent (Marieb,
1995).
iii)
Transverse humeral ligament:
This ligament spans the gap between the humeral tubercles (Marieb, 1995;
Martini et al., 2001).
2.2.2.3
Tendons:
The muscle tendons that cross the shoulder joint are far more important in
stabilizing the shoulder than the ligaments (Marieb, 1995, Hay & Reid, 1999;
Martini et al., 2001). The most important stabilizer is the tendon of the long head
of the biceps brachii muscle (Figure 4a) (Marieb, 1995). This tendon stretches
from the superior margin of the glenoid labrum, through the joint cavity, and then
exits the cavity and runs within the intertubercular groove of the humerus. This
way it secures the humerus tightly against the glenoid cavity (Martini et al.,
2001).
Four other tendons, together with their associated muscles, collectively called the
rotator cuff, encircle the shoulder joint and blend with the articular capsule
(Yokochi et al., 1989). The rotator cuff consists of the subscapularis,
supraspinatus, infraspinatus and teres minor muscles (Figure 12) (Marieb,
1995). Because of the arrangement of its muscles, the rotator cuff can be
severely stretched when the arm is vigorously circumducted. The humerus
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25
usually tends to dislocate downward, since the shoulders’ reinforcements are the
weakest inferiorly (Marieb, 1995; Martini et al., 2001).
Figure 6: Muscles crossing the shoulder and elbow joints, causing movement of
the arm and the forearm. (a) Anterior view of the superficial muscles of the
anterior thorax, shoulder and arm. (b) The biceps brachii muscle of the anterior
arm. (c) The brachialis muscle arising from the humerus, and the
coracobrachialis and subscapularis muscles arising from the scapula. (d) The
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extent of the triceps brachii muscle of the posterior arm, in relation to the deep
scapular muscles; the deltoid muscle of the shoulder removed (Marieb, 1995).
2.3 MUSCLES AND MOVEMENTS OF THE SHOULDER GIRDLE
2.3.1
Movements of the Shoulder Girdle:
All the movements of the scapula depend on the combined motion capabilities of
both the sternoclavicular and the acromioclavicular joints. The sternoclavicular
joint permits movement in almost all directions, including circumduction. The
acromioclavicular joint permits the gliding motion of the articular end of the
clavicle on the acromion, and also some rotation of the scapula both forward and
backward on the clavicle (Hay & Reid, 1999). The movements of the scapula in
combination with the clavicle are as follows:
i.
Adduction and abduction:
Adduction of the scapula occurs when the medial border of the scapula
moves toward the spine and abduction of the scapula when the medial border
moves away form the spine. Adduction can be seen when sticking out the
chest and pulling back the shoulders (Yokochi et al., 1989; Hay & Reid,
1999).
ii.
Elevation and depression:
Elevation is the upward movement of the scapula with no rotation, as in
raising the shoulders. The downward movement of the scapula is called
depression. Elevation and depression can be felt by placing the hand on the
scapula and the clavicle either separately or simultaneously while first lifting
the shoulders and then pushing them down again (Yokochi et al., 1989; Hay
& Reid, 1999).
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iii.
Rotation:
The axis of rotation can be either at the sternoclavicular or the
acromioclavicular joint. Upward rotation is the outward and upward movement
of the inferior angle of the scapula. Downward rotation is the inward and
downward movement of the inferior angle of the scapula (Hay & Reid, 1999).
2.3.2 Movements of the Shoulder Joint:
The movements of the glenohumeral joint should not be confused with those
movements of the shoulder girdle, although they usually occur together and
should be considered together. Extension, flexion, a slight degree of
hyperextension, abduction, adduction, circumduction, medial rotation and lateral
rotation may all occur at the shoulder joint, but their range of motion is limited if
there is no shoulder girdle involvement (Hay & Reid, 1999). During all flexion and
abduction motions of the glenohumeral joint there are simultaneous
scapulothoracic (shoulder girdle) movement. The scapula remains fixed through
the first 30º to 60º, but there may be motion at the joint until a stable position is
obtained, or the scapula may move on the chest wall. After 30º of abduction or
60º of forward flexion, there is a constant relationship between the humeral and
the scapula movement with two degrees of humeral movement for every one
degree of scapular rotation (Figure 7) (Yokochi et al., 1989; Hay & Reid, 1999).
Taken from the anatomical position, the full range of movement in flexion of the
arm above the head can only be accomplished if medial rotation of the humerus
occurs, whereas full abduction is possible from this position (Yokochi et al.,
1989). If abduction is attempted with the palm of the hand facing the thigh, the
range of motion is limited to approximately 90º. Lateral rotation will permit further
abduction from this point (Hay & Reid, 1999).
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Figure 7: A posterior view of the scapula and the humerus during abduction of
the humerus. (A) scapulothoracic angle, (B) glenohumeral angle (Hay & Reid,
1999).
2.3.3
Scapulohumeral Rhythm:
During the first 30º of abduction and the first 60º of forward flexion, the scapula
seeks stability on the thorax (Poppen & Walker, 1976). On the other hand,
research done by Freedman & Munro (1966) showed total scapular upward
rotation of 65º with total glenohumeral abduction of 103º by using radiographic
data for five positions of abduction. Their conclusion was that for every two
degrees of scapular motion there are three degrees of glenohumeral movement.
According to Doody et al. (1970) this discrepancy between the data of Freedman
& Munro (1966) and those of others may be due to the fact that motion was
allowed to occur in a coronal versus a scapular plane, the latter being 30º - 45º
anterior to the true coronal plane. Under loaded conditions the scapular
contribution gets called upon earlier in the range. It is generally agreed that the
ratio of two degrees of glenohumeral motion to every three degrees of scapular
movement is accurate, particularly when the total range of motion is considered
(MacConaill & Basmajian, 1969; Doody et al., 1970; Frankel & Nordin, 1980;
Michiels & Grevenstein, 1995; Soderberg, 1997; Roetert, 2003). Overall, we
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29
would concede that the range of scapular motion does not likely exceed 60º and
the glenohumeral joint does not exceed 120º (Soderberg, 1997). The primary
motion that occurs at the sternoclavicular during arm raising is elevation. Poppen
& Walker (1976) reported an approximate 35º - 45º elevation of the clavicle by
evaluating acromial elevation. Most of this motion occurred during the first 90º of
elevation, meaning a 4º - 5º of elevation during each 10º of the first half of the full
range of arm elevation. Together with this sternoclavicular elevation, motion also
occurs at the acromioclavicular joint. The coracoclavicular ligament pulling action
on the inferior aspect of the clavicle causes the clavicle to rotate around its own
axis (Soderberg, 1997; Martini et al., 2001; Roetert, 2003). This posterior rotation
of the clavicle creates movement of the lateral clavicle on the acromion. During
the first 30º and from 135º to the maximum level of elevation, rotation of the
acromioclavicular joint occurs around the longitudinal axis of the clavicle. The
summation of these motions at the sternoclavicular, glenohumeral,
scapulothoracic and the acromioclavicular joint creates the ability of humans to
raise their arms above their heads (Soderberg, 1997).
2.3.4.
Muscles of the Shoulder:
There are four important pairs of muscles on the posterior aspect of the trunk
that act on the shoulder girdle:
a.
The Trapezius:
The trapezius is a large triangular-shaped muscle that can be divided into four
parts each with it own innervations (Figure 8).
i)
The upper part is a thin sheet like muscle that is attached from
the base of the skull to the neck of the clavicle. Its prime function is
elevation of the scapula and it is therefore very active during weight
bearing of the upper limb such as carrying a suitcase.
ii)
The second part is immediately below the first part and is attached to the
acromion. This part is involved in the elevation and upward rotation and
assists in adduction.
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iii) Next below is the third part and the prime mover for adduction of the
scapula.
iv)
The fourth part is involved with the upward rotation and depression
and assists in adduction (Hay & Reid, 1999; Martini et al., 2001).
Figure 8: The trapezius (T) in action indicating the four heads (Hay & Reid,
1999).
The primary role of the trapezius is to support the upper limb upon the axial
skeleton (Soderberg, 1997). It also causes and maintains upward rotation of the
scapula on the thorax (Bearn, 1961).
b.
The Levator Scapula:
The levator scapula is a small muscle that is situated deep to the upper part of
the trapezius. Its main function is elevation of the shoulder (Hay & Reid, 1999;
Martini et al., 2001).
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c.
The Rhomboid Major and Minor:
These muscles are located below the trapezius. They are strong adductors of the
scapula and they also contribute to downward rotation of the scapula (Hay &
Reid, 1999; Martini et al., 2001).
There are two major pairs of muscles that act on the shoulder girdle on the
anterior aspect of the trunk:
d.
The Serratus Anterior:
This is a broad muscle situated on the lateral side of the chest where it originates
on the upper eight or nine ribs (Hay & Reid, 1999). The serratus anterior has a
serrated appearance and is easily visible on a well-muscled person. This muscle
is inserted into the medial border of the scapula and it abducts the scapula while
holding it in close proximity to the thoratic cage when it contracts during a
forward-pushing action (Martini et al., 2001). A primary responsibility is thought to
be the motion of protraction, which is the gliding of the scapula on the wall of the
thorax. Also, the lower part of the serratus assists with the upward rotation of the
scapula (Soderberg, 1997). A strengthened and shortened serratus anterior
reduces the condition of the protruding inferior angle of the scapula and it is then
referred to as a winged scapula (Hay & Reid, 1999; Martini et al., 2001).
e.
The Pectoralis Major and Minor:
The pectoralis minor is a small muscle that is found deeper to the pectoralis
major. It is inserted into the coracoid process and depresses the superior lateral
angle of the scapula during contraction. This causes the inferior angle to protrude
if it is not supported by the serratus anterior (Hay & Reid, 1999; Martini et al.,
2001). The pectoralis major existed of superficial and deep layers until
differentiation started to take place. In most animals the pectoralis minor attaches
to the humerus instead of the coracoid process. However, in human beings, the
coracohumeral ligament can be considered as a vestige of the former humeral
attachment (Soderberg, 1997). The pectoralis major is unquestionably important
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32
for the powerful movements of the arm across the trunk (Soderberg, 1997;
Roetert, 2003).
Together, the serratus anterior and the upper and lower fibers of the trapezius
cause effective scapular upward rotation that can be achieved as the arm is
elevated over the head (Lehmkuhl & Smith, 1996). The trapezius and the
serratus anterior also act as an effective force couple in the accomplishment of
scapular upward rotation (Soderberg, 1997). In order to demonstrate this,
consider the axis of rotation to be in the centre of the scapula (Figure 9)
(Soderberg, 1997). As upper, lateral fibers of the trapezius pull upward on the
distal aspect of the spine of the scapula, the inferior fibers of the serratus anterior
pull the inferior angle of the scapula in a lateral and anterior direction. Thus, the
muscles exert torque that results from the effective use of the principle of force
couples (Soderberg, 1997). According to Inman et al. (1944), the trapezius lost
some of the fibers (due to the lack of use) that run parallel to the spine of the
scapula. Also, the serratus anterior is unanticipated since this muscle has
already been separated from the levator scapulae muscle by virtue of loss of the
intermediate fibers that formerly connected these two muscles. The relation of
these two muscles can be seen by their innervations. The levator that is supplied
by cervical roots 3, 4 and a part of 5, and the C5, C6, and C7 innovations of the
serratus anterior is an indication that these two muscles were once continuous
with each other (Warwick & Williams, 1989; Sonnery-Cottot et al., 2002).
The rhomboids, teres major and latissimus dorsi form couples for purposes of
lowering the arm to the side. This action is produced in pull- ups or during high
velocity activities such as the tennis serve (Soderberg, 1997).
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Figure 9: Representation of the action of the serratus anterior and the lower
fibers of the trapezius as a force couple (Soderberg, 1997).
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Table 1: Muscles acting on the shoulder girdle (Hay & Reid, 1999; Martini et
al., 2001).
Muscle
Levator scapulae
Location
Neck (posterior)
Origin
Insertion
First 4 cervical
Medial border of
vertebrae
scapula from the
Action
Elevates scapula
spine to the superior
angle
Pectoralis minor
Chest (deep to
rd
th
Ribs (3 to 5 )
pectoralis major)
Scapula (coracoid
Depresses scapula,
process)
pulls shoulder
forward
Rhomboid major
Deep upper back
Spinous process
Medial border of
Adducts and rotates
(2 to 5 thoracic
scapula (spine to
scapula
vertebrae)
inferior angle)
nd
Rhomboid minor
Deep upper back,
th
Ligamentum nuchae
Scapula spine (root)
Adducts scapula
Medial border of
Abducts scapula
th
superior and
(lower part), 7
superficial to major
cervical and 1st
thoracic vertebrae
Serratus anterior
Lateral thorax
Upper 8 or 9 ribs
scapula
Trapezius
Upper back and
Occipital
Clavicle, spine of
Adducts and rotates
neck (superficial)
protuberance,
scapula, and
scapula, elevates
ligamentum nuchae,
acromion process
and depresses
spine of 7th cervical
scapula, extends
and all thoracic
neck
vertebrae
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Table 2: Muscle acting on the shoulder joint (Hay & Reid, 1999; Martini et al.,
2001).
Muscle
Coracobrachialis
Deltoid
Infraspinatus
Latissimus dorsi
Location
Upper arm (medial)
Origin
Insertion
Action
Scapula (coracoid
Humerus (middle of
Flexion and
process)
medial surface)
adduction
Anterior, lateral and
Clavicle, scapula
Deltoid tuberosity of
Abducts arm, Parts:
posterior upper
(acromion and
humerus
flexes, extends and
surface of humerus
spine)
Posterior surface of
Scapula
Greater tuberosity of
Rotates humerus
scapula below spine
(infraspinous fossa)
humerus
laterally
Lower back
Vertebrae spines
Humerus (bicipital
Adducts, extends
groove)
and medially rotates
(superficial)
rotates
th
(thoracic 6 through
th
12 lumbar and
humerus
sacral), lumbosacral
fascia, crest of
ileum, muscular
slips from lower 3 or
4 ribs
Clavicular
Chest
Clavicle (medial
Humerus (lateral lip
Flexes and medially
half)
of bicipital groove)
rotates humerus
Sternum and costal
Humerus (lateral lip
Extends, adducts
cartilages of true
of the bicipital
and medially rotates
ribs
groove)
humerus
Posterior surface of
Scapula
Humerus (greater
Adducts humerus
scapula above spine
(supraspinous
tuberosity)
(assists)
pectoralis
Sternocostal
Chest
pectoralis
Supraspinatus
fossa)
Teres major
Inferior angle of
Scapula (dorsal
Humerus (bicipital
Adducts, extends
scapula to humerus
surface, inferior
groove)
and medially rotates
angle)
Teres minor
humerus
Immediately
Scapula (dorsal
Humerus (greater
Adducts and rotates
superior to teres
surface of lateral
tuberosity)
humerus laterally
major
border)
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2.3.5 Muscle Groups and Surface Anatomy:
There are eleven muscles that cross the shoulder joint and contribute to motion.
The muscle groups of the shoulder joint and their prime movers are the following:
i.
Shoulder Flexors: Clavicular Pectoralis and Anterior Deltoid:
The clavicular pectoralis is the upper portion of the large fan-shaped muscle of
the chest, the pectoralis major (Hay & Reid, 1999). There is an increase in
activity that occurs in this head of the muscle during flexion with maximum
activity being reached at 115º of flexion (Yokochi et al., 1989; Hay & Reid, 1999;
Martini et al., 2001).
The anterior deltoid is a superficial muscle that may be observed and palpated
with the arm abducted to 90º and is most active during resisted flexion (Martini et
al., 2001). Inman et al. (1944) stated that the deltoid makes up approximately
41% of the total mass of the human abductor group. Today this value would be
considered “conservative” (Soderberg, 1997). Muscle forces generate tensile
loads at some given location with respect to an axis of rotation. The result is that,
depending on the size of the tensile force and the perpendicular distance from
which the force is applied to, will determines the resultant torque (Yokochi et al.,
1989; Soderberg, 1997). Considering the anterior deltoid fibres while viewing the
body in a frontal plane, they are superior to the axis of rotation (Figure 10a)
(Soderberg, 1997). Therefore the muscle’s function for this plane is abduction.
The same muscle viewed from a superior point will show that the muscle
essentially passes anteriorly to the axis of rotation, producing internal rotation
(Figure 10b) (Soderberg, 1997; Martini et al., 2001). Finally, in viewing the
sagittal plane, the anterior location leads to the conclusion that a muscle
contraction will cause flexion (Figure 10c) (Soderberg, 1997).
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Figure 10: Triplanar diagrammatic view of the shoulder. (a) Superior, (b) Frontal,
and (c) Sagittal (Soderberg, 1997).
In addition to these muscles, the coracobrachialis and the short head of the
biceps also assist shoulder flexion (Hay & Reid, 1999).
ii. Shoulder Extensors: Sternocostal Pectoralis, Latissimus Dorsi and
Teres Major:
The active contraction of the sternocostalis pectoralis, latissimus dorsi and the
Teres major muscles makes resisted shoulder extension possible, which is found
in activities such as rope climbing and pull-up exercises (Hay & Reid, 1999). The
sternocostal pectoralis is the lower, larger part of the pectoralis muscle (Marieb,
1995). The latissimus dorsi is a very broad muscle on the back and it is
superficial, except for a small part that is covered by the lower part of the
trapezius (Hay & Reid, 1999; Martini et al., 2001). It is a very powerful extensor
and becomes very prominent in athletes where the shoulder extensor muscles
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38
are frequently used, for example the propulsive phase of swimming (Hay & Reid,
1999). The teres major are active during extension against resistance but
become inactive during motions without resistance.
The posterior deltoid and the long head of the biceps assist during shoulder
extension (Hay & Reid, 1999).
iii. Shoulder Abductors: Middle Deltoid and Supraspinatus:
In the deltoid muscle, the greatest activity occurs between 90º and 180º of
abduction. The middle deltoid is a multipennate muscle that abducts the shoulder
joint and can be felt just lateral to the acromion when the arm is abducted to 90º
(Hay & Reid, 1999). The supraspinatus is found just superior to the spine of the
scapula and is deep to the deltoid and the trapezius. It is an initiator of abduction
but it also assists the deltoid through 110º of abduction. Full abduction is
achieved through the assistance of the anterior deltoid, clavicular pectoralis and
the long head of the biceps (Hay & Reid, 1999; Martini et al., 2001).
iv. Shoulder Adductors: Sternocostal Pectoralis, Latissimus Dorsi and
Teres Major:
The so-called “iron cross”, a gymnastic move, is held by various vigorous
contractions of these adductor muscles in order to prevent further abduction that
would occur if gravity were allowed to pull the gymnast downward. The short
head of the biceps and the long head of the triceps assist adduction, whereas the
subscapularis and the coracobrachialis also assist when the arm is abducted
above 90º (Hay & Reid, 1999).
v. Inward Rotators: Teres Major and Subscapularis:
Medial rotation is achieved by the action of the subscapularis and the teres major
but is assisted by the anterior deltoid, clavicular and the sternocostal pectoralis,
latissimus dorsi and the short head of the biceps (Hay & Reid, 1999; Martini et
al., 2001).
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vi. Lateral Rotators: Teres Minor and Infraspinatus:
The posterior deltoid assists the prime movers of lateral rotation, the teres minor
and the infraspinatus (Martini et al., 2001).
vii. Horizontal Adduction: Clavicular and Sternocostal Pectoralis, Anterior
Deltoid and the Coracobrachialis:
Horizontal adduction is performed by the contraction of the clavicular and the
sternocostal pectoralis, anterior deltoid and the coracobrachialis muscles and is
assisted by the short head of the biceps (Hay & Reid, 1999; Martini et al., 2001).
viii. Horizontal Abduction: Middle and Posterior Deltoid, Infraspinatus and
Teres Minor:
The middle and posterior deltoid, infraspinatus and teres minor are responsible
for horizontal abduction and are assisted by the latissimus dorsi and teres major
muscles (Hay & Reid, 1999; Martini et al., 2001).
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2.3.6 Prime Muscles Used in Tennis:
Figure 11: The primary muscles used during the tennis serve (Roetert &
Ellenbecker, 1998).
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Before looking at training programmes for the shoulder, it is important to know
exactly what muscles are used during the different strokes in tennis. These
frequently used muscles must be the target in the strength training programme,
as well as those muscles that stabilize and decelerate the body. The strengthtraining programme must then emphasize their concentric and eccentric actions
(Figure 11) (Roetert, 2003).
a.
Muscles used in the forehand drive and volley:
•
Anterior deltoid;
•
Pectorals;
•
Shoulder internal rotators;
•
Elbow flexors (biceps); and
•
Serratus anterior.
(Chu, 1995; Roetert & Ellenbecker, 1998)
b.
Muscles used in the one-handed backhand drive and volley:
•
Rhomboids and middle trapezius;
•
Posterior deltoid;
•
Middle deltoid;
•
Shoulder external rotators;
•
Triceps; and
•
Serratus anterior.
(Chu, 1995; Roetert & Ellenbecker, 1998)
c.
Muscles used in the two-handed backhand drive:
Non-dominant side:
•
Pectorals;
•
Anterior deltoid; and
•
Shoulder internal rotators.
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Dominant side:
•
Rhomboids and middle trapezius;
•
Posterior deltoids;
•
Middle deltoids;
•
Shoulder external rotators;
•
Triceps; and
•
Serratus anterior.
(Chu, 1995; Roetert & Ellenbecker, 1998)
d.
Muscles used in the serve and overhead:
Arm swing:
•
Pectorals;
•
Shoulder internal rotators;
•
Latissimus dorsi; and
•
Triceps.
Arm extension:
•
Triceps.
Wrist flexion:
•
Wrist flexors.
(Chu, 1995; Roetert & Ellenbecker, 1998)
The primary muscles that hold the humerus head in the glenoid cavity are the
rotator cuff muscles (Figure 12). The rotator cuff consists of four muscles:
i.
Supraspinatus;
ii.
Infraspinatus;
iii.
Teres minor; and
iv.
Subscapularis.
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(Roetert & Ellenbecker, 1998; Roetert, 2003)
Figure 12: The Rotator cuff muscle (Marieb, 1995).
These four muscles originate back on the scapula and insert in the shoulder to
form a cuff surrounding the humerus (Roetert & Ellenbecker, 1998). According to
Roetert & Ellenbecker (1998) the rotator cuff is active during all the tennis
strokes. It accelerates the arm forward during the strokes and the serve and then
slows the arm down after ball impact and during the follow – through phase.
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In spite of the relatively small individual muscle masses, the collective functions
of the muscles of the rotator cuff become important in normal and pathological
motions (Marieb, 1995; Hay & Reid, 1999). The rotator cuff is so labeled because
of its affect upon the glenohumeral joint. Slips from all these muscles are
intimately woven into the capsule of the glenohumeral joint, strengthening and
reinforcing the capsule. The weakest portion of the capsule is the inferior part
where the cuff muscles contribute few reinforcing fibers (Soderberg, 1997). Saha
(1971) calls the rotator cuff muscles the “steerers”, because they are mainly
responsible for the rolling of the head of the humerus in the glenoid in different
elevations, while the prime mover is raising the arm. In the research done by
Saha (1971), electromyographic evidence was used to confirm the role of the
subscapularis and the infraspinatus as stabilizers in the early range. He also
demonstrated the electrical activity in the infraspinatus, almost solely, in the
terminal phases of arm elevation.
2.4
ANALYSIS OF THE SHOULDER IN TENNIS-SPECIFIC MOVEMENTS
The following review is meant to highlight the particular muscles that accelerates,
decelerates and stabilize the upper extremity during isolated movement patterns
common in tennis.
2.4.1 The Serve:
According to Yoshizawa et al. (1987) muscular activity of the shoulder and
forearm are significantly higher during the serve than during ground strokes.
The serve can be divided into four stages:
i.
“Windup”:
This phase is characterized by the initiation of the serving stance to the ball
toss by the contra lateral arm. The muscular activity in both the shoulder and
forearm are very low in this phase (Yoshizawa et al., 1987; Ellenbecker,
1995; Roetert, 2003).
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ii.
“Cocking phase”:
This phase begins after the ball toss and terminates at the point of maximal
external rotation of the glenohumeral joint of the racquet arm (Yoshizawa et
al., 1987; Morris et al., 1989; Ellenbecker, 1995).
High muscular activity has been reported in the dominant arm during the
cocking phase in the following muscles:
•
Serratus anterior (70%);
•
Supraspinatus (53%);
•
Infraspinatus (41%);
•
Biceps brachii (39%); and
•
Subscapularis (25%).
(Yoshizawa et al., 1987; Ellenbecker, 1995)
High muscular activity has been reported in the following areas during the
forceful internal rotation of the glenohumeral joint:
•
Pectoralis major;
•
Latissimus dorsi;
•
Subscapularis; and
•
Serratus anterior.
(Morris et al., 1989; Ellenbecker, 1995)
High muscular activity has been reported in the following areas during
acceleration:
•
Pectoralis major;
•
Deltoid;
•
Trapezuis; and
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•
Triceps.
(Yoshizawa et al., 1987; Morris et al., 1989; Ellenbecker, 1995)
iii.
Ball Contact:
Studies done by Miyashita et al. (1980), Yoshizawa et al. (1987), Rhu et al.
(1988) and Roetert (2003) show a relative silence of electrical activity in the
acceleration muscles during impact with a peak activity occurring just prior to
impact. Only the infraspinatus remains active during impact while stabilizing
the shoulder. The activity level of the biceps serves an extremely important
function in the late acceleration by decelerating the forceful elbow extension
in order to prevent hyperextension of the elbow prior to ball impact (Rhu et el.,
1988; Ellenbecker, 1995). This vital function of the biceps reinforces the
importance of eccentric muscular training of the biceps in rehabilitation
programmes of the shoulder as well as the elbow (Morris et al., 1989;
Ellenbecker, 1995).
iv.
The follow-through phase:
This final phase begins after ball impact (Morris et al., 1989; Yoshizawa et
al., 1987; Ellenbecker, 1995).
High muscular activity levels in the following muscle groups characterize this
phase:
•
Posterior rotator cuff (40%);
•
Serratus anterior (53%);
•
Latissimus dorsi (48%); and
•
Biceps (34%).
(Rhu et al., 1988; Ellenbecker, 1995; Hay & Reid, 1999)
Forceful eccentric muscular contractions are necessary, after the electrical
silence of the shoulder musculature during ball impact, to decelerate the
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humerus and to maintain glenohumeral joint congruity. The distal musculature
shows very low activity during the follow-through phase, with the exception of
the biceps (Morris et al., 1989).
2.4.2
Ground Strokes:
The forehand and the backhand can be broken down into three phases:
i.
Preparation phase:
The muscular activity is very low during the preparation phase in both the
shoulder and the forearm, with exception of the wrist extensors on the
forearm (Rhu et al., 1988; Schmidt-Wiethoff et al., 2003).
ii. Acceleration phase:
Forehand:
High muscular activity levels are found in the:
•
Subscapularis;
•
Biceps;
•
Pectoralis major;
•
Serratus anterior;
•
Wrist flexors; and
•
Pronator teres.
(Rhu et al., 1988; Morris et al., 1989; Montalvan et al., 2002)
It is important to note that vigorous topspin of the forehand is not produced by
hyperpronation of the forearm, but rather a low-to-high swing pattern with the
entire upper extremity (Groppel, 1986; Schmidt-Wiethoff et al., 2003).
Backhand:
High muscular activity levels are present in the:
•
Deltoids (88%);
•
Supraspinatus (73%);
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•
Infraspinatus (71%);
•
Biceps (45%);
•
Latissimus dorsi (45%);
•
Serratus anterior (45%); and
•
Wrist extensors: the predominant muscle group during this phase.
(Rhu et al., 1988; Morris et al., 1989; Montalvan et al., 2002)
iii.
The follow-through phase:
Forehand:
The forehand groundstrokes are characterized by moderately high activity of
the following muscle groups:
•
Serratus anterior;
•
Subscapularis;
•
Infraspinatus; and
•
Biceps.
(Rhu et al., 1988; Montalvan et al., 2002)
Backhand:
Moderately high muscular activity was found in the:
•
Biceps;
•
Middle deltoid;
•
Supraspinatus; and
•
Infraspinatus.
(Groppel, 1986; Rhu et al., 1988; Montalvan et al., 2002)
The activity during the follow-through phase was lower than during the
acceleration phase (Morris et al., 1989).
According to this above-mentioned review, a clinically applicable premise
regarding the importance of the rotator cuff, scapular stabilizers (serratus
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anterior), and the distal forearm musculature (wrist extensors) can be
formulated. A working knowledge of the active muscle in the tennis serve and
the groundstrokes assists in the formulation of both a preventative
conditioning programme as well as a rehabilitation programme for the injured
tennis player (Ellenbecker, 1995; Montalvan et al., 2002; Schmidt-Wiethoff et
al., 2003).
2.5 PHYSICAL DEMANDS OF TENNIS
It is generally accepted that the adaptability (learning effect) of a person rises
with the reduction of the number of factors to which they have to adapt. It is thus
very important to direct the athletes’ attention to the development of highly
specific means of training (Muller et at., 2000). In order to develop a training
procedure that is highly orientated toward competition in a specific type of sport,
the following conditions are important:
•
Thorough knowledge of the specific parameters relevant to performance in
the specific sport;
•
Scientific tests that cover all the sport-specific parameters and that allow
for the classification of the results; and
•
Training methods and specific exercises that fulfill the standard criteria for
the specific means of training (Menzel, 1990; Muller et al., 2000).
When one looks at specific strength and power training, the ‘principle of dynamic
correspondence’ should be taken into consideration during the design of the
exercise programme. This implies that the special exercises must be in harmony
with those parameters of movement that characterize the structure of competitive
technique (Menzel, 1990; Roetert, 2003). The advantage of co-ordinative affinity
between training and competitive exercises is that it results in favourable training
stimuli in the muscular relevant to the specific movement. It also has the
advantage that the specific neural mechanisms are developed, which improve
the strength in concrete execution of the movement (Muller et al., 2000).
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Researchers, such as Roetert & Ellenbecker (1998) characterize tennis as a
sport in which players must respond to a continuous series of emergencies. This
includes sprinting to the ball, changing direction, reaching, stretching, lunging,
stopping and starting. All these characteristics in combination with proper
balance and technique throughout a match are critical for optimal performance
on the court. Taking all these characteristics into consideration, players must
address flexibility, strength and endurance, power, agility and speed, body
composition, aerobic and anaerobic fitness in order to improve their tennis game
(Menzel, 1990, Roetert & Ellenbecker, 1998; Gokeler et al., 2001 ).
2.5.1 Physiology of flexibility:
Flexibility can be defined as the degree to which the muscles, tendons, and
connective tissues around the joints can elongate and bend (Burnham et al.,
1993; Roy et al., 1995; Kirshblum et al., 1997; Roetert & Ellenbecker, 1998,
Salisbury et al., 2003). If skeletal muscles are to perform normally, the brain must
be continually informed of the current state of the muscles, and the muscles also
have to exhibit healthy tone. Healthy tone is the resistance of the muscle to
active or passive stretch at rest (Marieb, 1995).
There are two requirements for healthy tone:
1.
The transmission of information from muscle spindles and Golgi Tendon
organs to the cerebellum and cerebral cortex; and
2. The stretch reflexes that are initiated by the muscle spindles, which monitor
the changes in muscle length (Marieb, 1995).
In tennis a player is required to make shots that places body parts in extreme
ranges of motion. If the player can maintain strength throughout a flexible,
unrestricted range of motion it will help prevent injury and enhance performance
(Roy et al., 1995; Roetert & Ellenbecker, 1998; Salisbury et al., 2003).
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Although flexibility training is an important component of a quality-conditioning
programme, it is often overlooked and least adhered to (Kirshblum et al., 1997;
Salisbury et al., 2003). According to Roetert & Ellenbecker (1998), this is due to
the following reasons:
•
Stretching doesn’t always feel good;
•
The benefits of flexibility on court is not obvious to the player;
•
Most players don’t have specific, individualized guidelines on when, how
or what to stretch for tennis; and
•
Flexibility receives not as much emphasis by coaches than the other
components of conditioning.
2.5.1.1 Types of flexibility:
a. Static stretching:
Static flexibility is an indication of the amount of motion that one has around a
joint or series of joints while at rest (Burnham et al., 1993; Kirshblum et al., 1997;
Roetert & Ellenbecker, 1998; Salisbury et al., 2003).
Recommendations for static stretching:
(According to Roetert & Ellenbecker, 1998)
•
Warm-up for 3-5 minutes (Burnham et al., 1993; Salisbury et al., 2003);
•
The focus must be on slow, smooth movements with controlled breathing.
Firstly, inhale deeply, then exhale as you stretch to the point of motion just
short of pain, then ease back slightly. The static stretch position must be
held for 15 to 20 seconds as you breathe normally and repeated 2 to 3
times (Burnham et al., 1993; Kirshblum et al., 1997; Salisbury et al.,
2003);
•
You should not feel intense pain. If a stretch hurts, or has a burning
sensation, you are stretching too far;
•
Always stretch your tight side first (Burnham et al., 1993);
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•
Perform the stretch only to your limits (Roy et al., 1995; Salisbury et al.,
2003);
•
Never lock your joints in a stretch (Burnham et al., 1993; Salisbury et al.,
2003);
•
Keep the movement smooth and do not bounce (Burnham et al., 1993;
Salisbury et al., 2003);
•
Always stretch the larger muscle groups first, and repeat the same routine
each day (Kirshblum et al., 1997); and
•
An ideal time for stretching is after aerobic activity when the muscles are
warm (Burnham et al., 1993; Roetert & Ellenbecker, 1998; Salisbury et al.,
2003).
b.
Dynamic stretching:
Dynamic flexibility describes the active range of motion about a joint or series of
joints and it represents the amount of movement the player has available for
executing serves, groundstrokes and volleys (Burnham et al., 1993; Roetert &
Ellenbecker, 1998; Salisbury et al., 2003).
Dynamic flexibility is limited by the following:
•
The joint structure’s resistance to motion;
•
The ability of the soft connective tissue (muscles and tendons) to deform; and
•
The neuromuscular components of the body, including the nerves (Roy et al.,
1995; Roetert & Ellenbecker, 1998).
Recommendations for dynamic stretching:
(According to Roetert & Ellenbecker, 1998)
•
Swing the racquet through each motion arc for the forehand, backhand, and
serving movements;
•
Reach up with alternate arms, as if you are climbing up a ladder. Incorporate
your trunk in each movement;
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•
Bend to each side, keeping the hands on the hips;
•
With the racquet held overhead, hold on to the ends of the racket and bend
side to side;
•
Still holding the racquet with your hands on the end, rotate your trunk by
twisting slowly from side to side;
•
Perform a bicycle motion with alternate legs, drawing progressively larger
circles; and
•
March with alternate legs until the knees are eventually up at nose height.
2.5.1.2
i.
Factors influencing flexibility:
Heredity:
Your overall flexibility potential is determined by your body design. Most people
tend to be inflexible, though some are loose jointed and hyper-flexible (Roetert &
Ellenbecker, 1998; Salisbury et al., 2003). The shape and orientation of joint
surfaces, as well as the construction and design of the joint capsule, muscles,
tendons and ligaments are some of the body designs that influences our flexibility
(Burnham et al., 1993; Kirshblum et al., 1997).
ii.
Neuromuscular components:
When a muscle is stretched too quickly, the muscle spindle sends a message to
the central nervous system to contract that muscle (Burnham et al., 1993). This
stretch reflex causes the muscle to shorten and contract and therefore hinders
the stretching process. This is the reason why we recommend slow, gradual
movements during stretching in order to minimize the reflex action of the muscle
spindle and to enhance the stretching process (Burnham et al., 1993; Roetert &
Ellenbecker, 1998).
iii.
Tissue temperature:
Heat increases the elongation and bending properties of soft tissue in the body.
By warming up before stretching it raises the body’s core temperature and it will
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give you greater gains in flexibility with less micro trauma to the tissues being
stretched (Roetert & Ellenbecker, 1998; Salisbury et al., 2003).
2.5.1.3 Areas that need flexibility training:
Tennis places tremendous demands on different body parts in their extremes of
motion (Burnham et al., 1993; Salisbury et al., 2003). For example, the range of
motion that the shoulder needs during the external rotation of the serving action
stresses the front of the shoulder. Most tennis players are flexible in the external
shoulder rotation due to the serving action, but have limited internal rotation on
their tennis playing side (Roy et al., 1995; Kirshblum et al., 1997). Other
examples of extreme ranges of motion in tennis includes:
•
Lateral movement that stresses the hip and groin;
•
Stabilizing muscle actions of the abdominal muscles during the serve; and
•
Explosive movement patterns of the calf and achilles tendon (Roetert &
Ellenbecker, 1998).
Throughout the match situation, players must generate great speed and force
while they are in an outstretched position. It is important to have a conditioning
programme that includes flexibility training to ensure that the athlete will have the
range of motion needed for optimal performance. In tennis it is essential to have
flexibility, combined with the ability to produce power in these extremes of motion
(Burnham et al., 1993). According to Roetert & Ellenbecker (1998) and SchmidtWiethoff et al. (2000), stretching alone will not prevent injuries or enhance
performance, but a balanced strength throughout a flexible, less restricted range
of motion will do so.
a. Shoulder and arm stretches:
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Trunk and shoulder stretch: (Figure 13)
i)
Focus:
Latissimus dorsi, triceps and the inferior capsule of the shoulder.
Start:
Stand with both arms overhead, holding the right elbow with the left
hand.
Action:
The left hand pulls the right elbow in behind the head. While
holding this position, bend the trunk to the left side. Repeat to the
other side (Burnham et al., 1993; Roetert & Ellenbecker, 1998).
ii)
Overhead stretch: (Figure 14)
Focus:
Intercostal muscles and the inferior capsule of the shoulder.
Start:
Stand with both arms overhead, the wrists crossed and the palms
together.
Action:
Stretch the arms slightly backwards and push them up as high as
possible. Bend slightly to either side to increase the stretch to your
trunk (Burnham et al., 1993; Roetert & Ellenbecker, 1998).
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Figure 13: Trunk and shoulder stretch.
iii)
Figure 14: Overhead stretch.
Scapular stretch: (Figure 15)
Focus:
Rotators of the shoulder and the scapular (upper back) muscles.
Start:
Stand by holding your right arm straight in front of you and placing
your left arm behind your right elbow.
Action:
Pull the right arm across your body with your left hand, but do not
allow the trunk to rotate. To help demonstrate this stretch, the
athlete can stand against the wall with both shoulder blades
touching the wall while performing the stretch (Burnham et al.,
1993; Roetert & Ellenbecker, 1998).
iv)
Shoulder squeeze: (Figure 16)
Focus:
Shoulders and the front of the chest.
Start:
Interlace the fingers behind the head, keeping the elbows straight
out to the side and the upper body in an upright, aligned position.
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Action:
Pull the elbows together behind the head and pull the shoulder
blades together in order to create tension through the upper back
and shoulders (Burnham et al., 1993; Roetert &Ellenbecker, 1998).
Figure 15: Scapular stretch.
v)
Figure 16: Shoulder squeeze.
Forearm flexor stretch: (Figure 17)
Focus:
Pronators and flexors of the forearm muscles.
Start:
The elbow is extended and the forearm supinated (palm up).
Action:
Use the opposite hand to stretch the wrist backward while keeping
the elbow straight (Roetert & Ellenbecker, 1998).
vi)
Forearm extensor stretch: (Figure 18)
Focus:
Extensors and supinators of the forearm muscles.
Start:
The elbow is extended and the forearm pronated (palm down).
Action:
Use the opposite hand to stretch the wrist downward while keeping
the elbow straight (Roetert & Ellenbecker, 1998).
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Figure 17: Forearm flexor stretch.
Figure 18: Forearm extensor
stretch.
2.5.1.4
a.
Benefits of Flexibility:
It allows sport-specific strengthening in extreme motions (Roetert &
Ellenbecker, 1998);
b.
It accommodates the stresses on the body by helping the tissue to
distribute the impact of shock and force loads more effectively (Roy et al.,
1995; Kirshblum et al., 1997; Salisbury et al., 2003);
c.
It lightens the intensity of work of the opposing muscle groups by providing
less restricted motion (Roetert & Ellenbecker, 1998);
d.
Flexibility enhances blood supply and tissue nourishment (Kirshblum et al.,
1997);
e.
It allows good form and posture without compensating from other body
segments (Burnham et al., 1993; Roy et al., 1995); and
f.
It helps to overcome imbalances created by tennis and by other daily
activities (Salisbury et al., 2003).
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2.5.2
Strength and Endurance:
According to Costill & Fox (1969), Kraemer et al. (1995) and Kraemer et al.
(2003) muscular power is a very important aspect in tennis and therefore
resistance training became an important tool to optimize the neuromuscular
performance factors related to the primary strokes. The classical model of
periodization of resistance training manipulates the intensity and volume of
exercise over time with the main intention of minimizing boredom, prevention of
overtraining and to reduce injuries (Matveyev, 1981; Fleck, 1999; Kraemer et al.,
2003). It was typically used by strength and power sports to peak physical
performance for major competitions. Due to the fact that not all sports are pure
strength and power sports, and also may have multiple competitions and long
seasons, a nonlinear or undulating model has been proposed. In this model
different training sessions could be rotated over a 7- to 10- day cycle (Costill &
Fox, 1969; Kraemer et al., 2003). A recent review of the literature done by Fleck
(1999) supported the hypothesis that periodization of resistance training can
result in greater maximal strength gains and may even result in greater motor
performance adaptations in comparison to the traditional resistance-training
programmes with limited variation in stimuli over long-term periods. Many
resistance-training programmes provide only a limited variation in the volume and
intensity used during training (Kraemer et al., 2003).
2.5.2.1 Weight Training:
In sport, weight training has become so important that it seems incredible that the
prejudices that once surrounded its use ever existed. One of the outstanding
reasons for the improvement in sport performance over the last thirty years has
been the increased use of weight training as an essential part of the athlete’s
conditioning programme (Kirkley & Goodbody, 1986; Meister; 2000; SchmidtWiethoff et al., 2000; Roetert, 2003). Due to the importance of muscular power in
tennis, resistance training has become a very important training tool to optimize
the neuromuscular performance factors related to the primary strokes in tennis
(Kraemer et al., 2003). Certain sports benefit more from weight training than
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others, but the most important aspect is that these gaps in some of the sports
needs to be filled by people qualified in the science of weight training in order to
benefit the sport (Roetert, 2003). The weight- training programme needs to be
adapted to the specific activity, because the needs of all sports differ. The
training programme of a tennis player will be totally different to the type of
training of a shot-putter (Kirkley & Goodbody, 1986; Kraemer et al., 2003).
In modern sport, including tennis, weight training has become more valuable than
before due to the increase of people devoting themselves to excellence in tennis.
Professional people in this field must preferably examine the training schedule
carefully. It is important to determine the type of exercises, sets and repetitions
that are suitable for tennis (Kirkley & Goodbody, 1986; Roetert, 2003).
a. The scientific basis of weight training:
Traditional weight training is based on the principle of ‘progressive overload’. In
order to raise the level of strength and stamina, the body must be subjected to an
increased resistance through heavier weights, higher repetitions or longer or
more frequent training sessions (Kirkley & Goodbody, 1986; Kraemer et al.,
2003). A good example of “progressive overload” is the lesson from the Greek
legend of Milo of Croton. Milo uses to carry a little calf daily, and as the calf grew
so did his strength. When the calf reached the age of four years, Milo was still
able to carry the bull because his body adapted to the greater demands placed
on it (Costill & Fox, 1969; Kirkley & Goodbody, 1986).
The following demonstrates the basic principles of weight training:
•
In order to increase strength or size, the body must be asked to perform
tasks, which it previously did not achieve;
•
The intensity of training must be increased gradually and steadily;
•
Training must be regular; and
•
The exercises must be specific (Kirkley & Goodbody, 1986; Ellenbecker et al.,
2002; Kraemer et al., 2003).
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The importance of specificity can’t be stressed enough (Costill & Fox, 1969;
Matveyev, 1981; Kirkley & Goodbody, 1986; Kraemer et al., 2003; Roetert,
2003). Various types of training have been subjected to research in recent years
as the desire for improvement has escalated (Kirkley & Goodbody, 1986;
Kraemer et al., 2003). One thing that strongly emerges, is the fact that training
must be geared to the particular sport for which the athlete is training for (Kirkley
& Goodbody, 1986; Fleck, 1999; Kraemer et al., 2003). In tennis, using weights
will help to develop explosive power and speed on court, muscle strength as well
as muscle endurance. What is important is that the athlete should be carefully
analysed in order to develop a programme according to his/her abilities. Only
then can be determined the kind of exercise, the number of repetitions and the
severity of the activity appropriate to the athletes needs. One of the reasons that
makes weight training so popular is because it is so versatile and can be adapted
to so many requirements (Kirkley & Goodbody, 1986; Roetert, 2003; Salisbury et
al., 2003).
Periodisation is very important in any sport, especially in tennis where the players
have to peak more than once a year and where the competition seasons are
throughout the year (Fleck, 1999; Kraemer et al., 2003). According to research
done by Kraemer et al. (2003), periodisation of resistance training produced
greater magnitudes of improvement in strength and sport-specific motor
performance than the traditional resistance training programmes where there are
limited variations in volume and intensity of training. The major difference
between these two training principles was the variation in intensity during each
week of the periodized programme. The effect of greater strength and power with
periodized training is most likely due to the ability to recruit more fast- twitch
motor units with the inclusion of the heavier loading (Sale, 1988;
Schmidtbleicher, 1988; Kraemer et al., 2003; Roetert, 2003). According to
studies done by Anderson & Kearney (1992) and Kraemer et al. (2003)
individuals that were exposed to heavier loads during training experienced
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greater improvement in maximal strength performance. Also, heavy resistance
training shows to be effective in increasing strength in female athletes over a 6month training period (Brown & Wilmore, 1974; Ellenbecker et al., 2002; Kraemer
et al., 2003).
b. The Physiology of Muscle Growth:
Psychological inhibition and learning factors can greatly modify one’s ability to
express muscular strength in the early phase of training. Though, the ultimate
limit for strength is determined by anatomical and physiological factors within the
muscle (McArdle et al., 1991).
i. Muscular Hypertrophy:
A fundamental biological adaptation that can be viewed to an increase in
workload is the increase in skeletal muscle size. This compensatory adjustment
leads to an increase in the muscle’s capacity to generate tension (Willmore,
1974; McArdle et al., 1991). According to Gollnick (1983) and Hakkinen (1988)
the muscular growth in response to overload training occurs primarily from an
enlargement or hypertrophy of individual muscle fibers. They found that the fasttwitch muscle fibers of weight lifters were 45% larger than those of healthy
sedentary people and endurance athletes.
ii. Hyperplasia:
The question whether the actual number of muscle cells increases with training is
often raised. If it does take place, to what extent does it contribute to muscular
enlargement in humans? (McArdle et al., 1991). Cross-sectional studies of body
builders with relatively large limb circumference and muscle mass failed to prove
that these athletes possessed a significant hypertrophy of individual muscle
fibers (MacDougall et al., 1980). This leaves open the possibility of hyperplasia in
humans with resistance training. It suggests either an inherited difference in
muscle fiber number or that muscle cells may adapt differently to the high
volume, high intensity training used by body builders compared with the typical
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low-repetition, heavy load system favoured by weight and power athletes
(Larsson & Tesch, 1986; Tesch, 1988). According to MacDougall (1984) the
enlargement of the existing individual muscle cells makes the greatest
contribution to muscular size with overload training.
2.5.3 Body Composition:
Another change that takes place with training, is the reduction in body fat
percentage. According to McArdle et al. (1991) adipose tissue increases in two
ways:
a. Cell hypertrophy: Existing fat cells are enlarged or filled with more fat; or
b. Fat cell hyperplasia: The total number of fat cells increase.
When a person reduces body size, there is a decrease in fat cell size, but no
change in the total cell number (McArdle et al., 1991). An increased calorific
output through endurance type exercise provides a significant option of
unbalancing the energy balance equation to bring about weight loss as well as a
desirable modification in body composition (Craig, 1983). The performance of
conventional resistance training programmes combined with calorific restriction,
results in the maintenance of lean body mass compared with a programme that
relies only on diet (McArdle et al., 1991).
According to Konig et al. (2001) and Kraemer et al. (2003) the progressive
adaptation of top ranked players induced by years of training and match play
included changes in the following:
-
heart size;
-
maximum oxygen intake;
-
onset of lactate production;
-
heart rate;
-
blood pressure;
-
hormonal regulation;
-
functional and structural alterations in the conducting arteries;
-
bone density; and
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-
muscle mass of the dominant arm.
2.5.3.1 Characteristics of female and male tennis players:
It is well documented by Willoughby (1993) that Woman’s upper body strength
differs from their lower body strength in terms of their initial strength and their
ability to adapt to training.
a. Anthropometrical Aspects:
There are no general differences between male and female up to the age of
approximately 12 years (Willoughby, 1993; Meister, 2000), although several
structural, functional, mental and physical differences can be observed in early
childhood (ITF Manual).
Table 3: The differences in weight distribution between males and females (ITF
Manual).
MALE
FEMALE
Bones:
20%
15%
Muscle:
40%
36%
Fat tissue:
20%
30%
Internal organs:
12%
12%
Blood:
8%
7%
Table 4: The differences in bones and joints between males and females (ITF
Manual).
ASPECT
MALE
FEMALE
Height:
Taller.
Shorter: 10-12cm.
Weight:
Heavier.
Lighter: 10-15kg.
Limbs:
Limbs, hands and feet are Limbs, hands and feet are
longer.
10% shorter which positively
affects their flexibility and
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agility, and due to the shorter
stroke lever arm, the power
of the stroke is reduced.
Trunk:
Longer: 38%.
Shorter: The center of gravity
is lower.
Skeleton:
It looks as if the limbs It
overhang.
Spine:
Upper
looks
as
if
the
trunk
is
more
overhangs.
part
is
less Upper
pronounced.
part
pronounced.
Lower part is shorter and the Lower part is longer and the
curvature less pronounced.
Shoulders:
curvature more pronounced.
Greater shoulder width with Less shoulder width with less
better-developed muscles – developed muscles – less
more power in the serve.
Arms:
power in the serve.
The formative arm structures The formative deviations in
at the elbows make them the arm-structures at elbow
more
suited
for
throwing levels make them less suited
actions.
for throwing actions.
Back:
Wider and stronger: 39cm.
Narrower and weaker.
Pelvis:
Narrower,
less
weaker.
flat
and Wider, flatter and stronger.
The disposition of the pelvic
bones
does
not
allow
elevation of the legs as
males.
Therefore
females
have less effectiveness in
speed and jumping actions.
Legs:
No genus valgus.
Different
which
lines
tends
of
to
support
converge
towards the knees (genus
valgus).
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Table.5: The differences in muscles between males and females (ITF Manual).
ASPECT
MALE
FEMALE
Weight of muscles More: 35kg.
Less: 23kg (50%less).
mass (30years):
Total
muscular 20-35% greater.
20-35% less.
power:
Muscular
There is more muscular There
development:
tone and mass for it is tone and mass for it is
dependent
Muscular
on
is
less
the dependent
muscular
on
testosterone levels.
testosterone levels.
Less.
More.
the
elasticity:
Type and number More
of muscular fibers:
fibers,
percentage
of
greater Less fiber.
oxidative
fibers and bigger oxidative
and glycolytic capacity.
Table 6: The differences in fat tissue between males and females (ITF Manual).
ASPECT
Percentage
MALE
of
tissue:
FEMALE
fat Usually
less
body
more
body
percentage. In athletes the percentage.
fat
percentage
of
fat Accumulated
fat
In
range sportswomen it can range
between 6 and 20%.
Distribution
fat Usually
in
between 12 and 30%.
the Accumulated in the gluteus
tissue:
abdomen and stomach.
Fat deposit:
Less: Body appears more More: Body appears less
muscular.
and hips.
muscular.
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b. Biological aspects:
The mean heart rate in trained tennis players aged between 20 and 30 years
ranges between 140 and 160 beats per minute during singles tennis matches.
This indicates an overall intensity of 60 to 70% of their VO2-max (Elliott et al.,
1985; Bergeron et al., 1991; Groppel & Roetert, 1992; Konig et al., 2001;
Kraemer et al., 2003). In professional players, this corresponds to an
ergometrically-determined workload within an aerobic/anaerobic transition range
on a treadmill of 13km/h for women and 14km/h for men at a 1.5º slope (Konig et
al., 2001). Despite the start and stop nature of tennis, heart rates during match
play are not distinct variations in accordance with the duration of the match
(Elliott et al., 1985). During fast and long rallies the heart rate can increase up to
190 – 200 beats per minute (Bergeron et al., 1991). However, these highly
intense periods are relatively short, and good condition assures a fast recovery
rate. This is advantageous for the concentration and the preparation for the next
rally (Konig et al., 2001).
The heart and the blood circulation display different characteristics in males and
females (Konig et al., 2001; ITF Manual). Due to the lower cardiac volume of
females in comparison with males, a lower level of oxygen occurs in the
circulatory system of woman (Groppel & Roetert, 1992). The respiratory
frequency in females is higher than in males due to the fact that females have
different thoracic breathing and also a lower respiratory volume. The pulmonary
capacity increases rapidly in both genders up to the age of 12. It then increases
very slowly or remains the same in females. Females need the same amount of
oxygen as males in order to perform the same activity, although it is harder for
females to achieve the same performance due to their lower pulmonary capacity
(Groppel & Roetert, 1992; ITF Manual).
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Table 7: The differences in the respiratory system between males and females
(ITF Manaul).
ASPECT
MALE
FEMALE
Weight of lungs (kg):
1.35
1.05
Pulmonary volume:
10% higher
10% lower
Pulmonary volume (sq. m):
90
80
Air volume or vital capacity (L):
5.5
4.1
Maximum oxygen intake (L/min):
3.1
2.4
Maximum oxygen per beat (cc):
15-20
10-13
Maximum respiratory rhythm (per min):
40
46
Maximum volume of deep breath (L):
5.0
3.5
Maximum respiratory capacity forced breathing 170
100
(L/min):
Maximum respiratory volume per minute normal 110
breathing (L/min):
90
(25% more)
Table 8: The differences in the circulatory system between males and females
(ITF Manual).
ASPECT
MALE
FEMALE
Heart weight (g):
350
300
Heart capacity (cc):
600-800
500-600
Heart size (cc):
750
550
Volume maximum heart beat (cc):
210
160
Volume maximum heart per minute (L/min):
37
25
Maximum beats (min):
190
180
Haemoglobin (%g):
16
14
Blood volume (ml/kg):
70-80
60-70
Blood total volume (L):
5.0
3.8
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c. Developmental aspects:
In a newborn baby the bones of males are heavier than females and the growing
proportion remains similar until puberty (Marieb, 1995). However, females reach
puberty earlier than males and therefore their bodies mature earlier (Roetert et
al., 1995, ITF Manual). The performance of females is lower than males due to
the specific functional and anatomical differences, which can be noticed from the
age of 7-8 years old. Due to the differences in development, females achieve
their maximum physical performance round about the age of 15-16 years while
men achieve it at 18-20 years of age. Due to the lower physical capacity of the
female athlete, the effort that she would have to put in, in order to perform the
same given task as a male, would be much bigger (Roetert et al., 1995; ITF
Manual).
Table 9: Characteristics that highlights differences in development between
males and females (ITF Manual).
FEMALE
CHARACTERISTICS
DEVELOPMENTAL STAGE
Overall
growth
period
shorter.
is Puberty is reached earlier and the final
structure is attained earlier.
Second period of growth is Maximum annual growth in height is 9cm for
shorter.
males and 7.7cm for females.
Faster sexual maturity.
The duration between the second stage of
development of the body and the second
period of growth is 6 months in females and
13 months in males.
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Table 10: Specific characteristics of the female body: Anatomical and functional
differences in systems and organs of the body (ITF Manual).
ASPECT
CHARACTERISTICS
Blood circulation:
Up to the age of 8 years, the size of the heart is similar
in both genders. Between 8 and 13 years it is bigger in
females, and after 13 years it is considerably smaller.
The heart efficiency in the post-puberty period is lower
in females and thus has a higher frequency of beats
than males.
Respiratory
The respiratory system of females is fully developed
system:
between 14 and 15 years as opposed to males at 18
years.
Metabolism:
The body weight of females is lower than males due to
the higher quantity of fat deposits.
Oxygen
Females have lower oxygen consumption than males.
consumption:
Oxygen
in The oxygen usage in muscles of males is more efficient
muscles:
than females.
Motor
From the age of 4 to 6 years the differences in motor
development:
development become evident. From the age of 8 years,
males displays better performance in power, agility,
speed, endurance and reflexes. During puberty (12 –
15 years) these differences increases even more.
d. Psychological aspects:
According to research done by the International Tennis Federation (ITF manual)
females have a higher desire to learn during practices, they are more disciplined
and they have a better ability to mix with and be part of the group. Women
display a greater need for a coach and other persons and are also more open
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and thankful for advice given to them. They have also shown that sportswomen
are more diligent and meticulous than sportsmen.
Table 11: The differences in motivation and interest between males and females
(ITF Manual).
ASPECT
MALES
Intensity of games and Active
activities preferred:
FEMALES
games
competition.
and Passive or quit games
with
less
muscular
activity.
Types of games and Throwing,
activities preferred:
speed
running, Jumping,
and
balancing,
power rhythmic exercises.
games.
Volume
activities
of
physical Higher.
Lower.
during
puberty:
Goals of practice:
They want to impress They want to show their
with
their
strength,
intelligence.
physical femininity and also the
ability
and characteristics of their
own personality.
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Table 12: The differences in psychological variables between males and females
(ITF Manual).
ASPECT
Anxiety:
MALES
Males
suffer
less
FEMALE
from Females suffer from anxiety
anxiety states than females states more frequently than
and
react
with
less males and they react with
sensitivity, impatience and more sensitivity, impatience
in a less nervous way.
and in a more nervous way.
Intellectually:
No difference.
No difference.
Aggressiveness:
More physical.
More
verbal,
acute
and
intellectual.
Decision
More confident.
Less confident when young
and they
making:
external
often look for
help
when
in
trouble.
Mental stability:
Less
psychologically
susceptible More
and
variable.
susceptible
less psychologically
variable,
and
more
tending
to
depression and states of
nervous excitement.
Confidence:
More self-confidence.
Less
self-confidence
and
more insecure. More worried
about their health and losing
their femininity.
Individualism:
Less individualistic.
Dependency:
More independent and less Less
influenced.
More individualistic.
independent,
more
influenced, more sensible
and more adaptable.
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2.6 INJURIES IN TENNIS PLAYERS
A good example of a tennis injury occurred at the 1996 Wimbledon
Championships, when Borris Becker hit a forehand service return and injured his
wrist to a shocking extent following that one shot. Borris then stated during an
interview that he had hit that forehand service return the same way he had hit it
thousands and thousands of times before. Borris was correct in analysing his
injury, that it had occurred in spite of not doing anything differently. This also
holds true for most injuries in tennis players (Roetert & Ellenbecker, 1998).
2.6.1 Causes of injuries in Tennis Players:
Most injuries in tennis players are typical overuse injuries (Priest & Nagel, 1976;
Kibler & McQueen, 1988; Roetert & Ellenbecker, 1998; Schmidt-Wiethoff et al.,
2000; Gokeler et al., 2001; Roetert, 2003). They result form repetitive stresses
and minor traumatic events, such as the effects on the shoulder due to serving
thousands of times, or the influence on the knee after playing hundreds of points
with pivots, turns and aggressive stops and starts. Overuse injuries occur due to
the fact that tennis players exert and produce forces in repetitive patterns that
cause minor traumas and tissue breakdown (Roetert & Ellenbecker, 1998,
Meister, 2000).
Tennis is a combination of endurance and power. Every match or training
session involves between 300 and 500 bursts of effort, each requiring power and
co-ordination of movement (Turner & Dent, 1996). According to Kibler &
McQueen (1988) and Ellenbecker (1995), there are specific physiological and
mechanical stresses imposed on the shoulder girdle in tennis that causes
characteristic anatomic adaptation. This can lead to subsequent overuse injuries
(Ellenbecker, 1995; Schmidt-Wiethoff et al., 2000; Kraemer et al., 2003). Serves
may be delivered at speeds of 176km/h and the players have to change direction
frequently and withstand forceful impacts with the ball (Turner & Dent, 1996). The
shoulder is one of the most mobile joints in the entire human body and due to its
large range of motion, it can become injured easily during tennis play (Hay &
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Reid, 1999; Gokeler et al., 2001; Montalvan et al., 2002). The glenuhumeral joint
consists of a ball (humerus) and socket (glenoid) without the benefit of a deep
socket that is found in the hip joint. Therefore, the muscles and the ligaments that
surround the shoulder must work harder in order to keep the ball in the socket
(Ellenbecker et al., 2002). Especially during rapid movements, which in tennis,
occur as fast as 2500 degrees per second. This speed is similar to the rotation of
the wheels on a bike traveling 51.2km/h and 417 times faster than the rotation of
the second hand on a clock! (Ellenbecker et al., 2002; Sonnery-Cottet et al.,
2002).
The modern tennis game encourages the use of maximum effort in order to
increase ball speed off the racquet and this results in larger forces being
absorbed by the body, more specifically, the shoulder (Turner & Dent, 1996;
Schmidt-Wiethoff et al., 2003). 70-80% of all tennis injuries are caused by
overuse (Ellenbecker, 1995; Turner & Dent, 1996; Kraemer et al., 2003). Two
such injuries that are common in tennis are rotator cuff tendonitis and humeral
epicondylitis (Priest & Nagel, 1976). Ellenbecker (1995) found in his study that
there was a 63% higher incidence of shoulder injuries among players with tennis
elbow than among players with no history of tennis elbow. Many young players
are actively involved in intensive tennis training programmes and according to
Turner & Dent (1996) the growing body is particular susceptible to damage. Due
to the larger forces being absorbed by the body and the growing body being
susceptible to injuries, as mentioned above, it necessitates that we carefully
investigate tennis injuries. More specifically, we need to investigate the warning
signs, their treatment and also what the coaches and trainers can do to reduce
the risk of injury (Turner & Dent, 1996; Gokeler et al., 2001; Schmidt-Wiethoff et
al., 2003).
Two of the most common shoulder injuries in tennis involve the rotator cuff and
the biceps long head tendon (Reece et al., 1986; Schmidt-Wiethoff et al., 2000;
Gokeler et al., 2001; Montalvan et al., 2002; Sonnery-Cottet et al., 2002). During
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the overhead upper extremity movements of the serve, the rotator cuff and the
biceps tendon are placed in a compromising position between the humeral head
and the coracoacromial arch. Neer (1983) and Ellenbecker (1995) described the
mechanism of subacromial impingement of the rotator cuff tendons under the
coracoacromial arch as the primary factor that contributes to overuse shoulder
injuries. A progression has been reported in the literature which starts at shoulder
impingement in the initial phase of oedema and tendon inflammation and
progresses to bursal side (superior surface) partial rotator cuff tears and
subsequent full-thickness tears (Bigliani et al., 1992; Meister & Andrews, 1993;
Montalvan et al., 2002).
Another factor that can lead to tendinous inflammation and progress to an
undersurface (articular side) rotator cuff tear is the intrinsic tendon overload
caused by high-intensity decelerative eccentric muscular contractions of the
posterior rotator cuff during the follow-through phase of the serve (Meister &
Andrews, 1993; Ellenbecker, 1995; Sonnery-Cottet et al., 2002).
The rotator cuff has got a stabilizing function in resisting:
•
Anterior translation;
•
Internal rotation;
•
Horizontal adduction; and
•
Distraction at the glenohumeral joint during the follow-through phase.
(Montalvan et al., 2002; Sonnery-Cottet et al., 2002)
This stabilizing function of the rotator cuff can be magnified in the shoulder in the
case of subtle instability (Meister & Andrews, 1993; Ellenbecker, 1995;
Montalvan et al., 2002; Schmidt-Wiethoff et al., 2003). Anterior instability of the
glenohumeral joint can be caused by attenuation of the glenoid labrum as well as
the capsuloligamentous complex (Wilk & Arrigo, 1993). Progressive attenuation
of these static stabilizers occurs with overhead activities like the serve and the
smash (Jobe & Bradley, 1989; Sonery-Cottet et al., 2002). The attenuation of the
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static stabilizers causes a greater demand on the dynamic stabilizers, which
involves the rotator cuff and the biceps long head. This can result in tendon
inflammation and progressive rotator cuff disease (Wilk & Arrigo, 1993; Gokeler
et al., 2001). The presence of instability in the tennis player’s shoulder can cause
tensile injury to the rotator cuff and it also subjects the rotator cuff to secondary
impingement or compressive lesions (Jobe & Bradley, 1989; Gokeler et al.,
2001). According to Ellenbecker (1995) both subacromial and articular surface
impingement have been reported in throwing shoulders where instability is
present.
According to Groppel (1986), Groppel & Roetert (1992) and Ellenbecker et al.
(2002) it is clear that non-optimal timing and a lack of whole-body contributions to
force generation and deceleration, subject an individual’s shoulder and elbow to
overuse injury. This can be seen in the presence of increased, as well as
overlapping muscular activity patterns across the four stages in the tennis serve
(as described in 2.4.1).
Tennis injuries can be divided into two categories: acute and chronic. Acute
injuries refer to a new injury or complaint from the time it occurs and the short
time following the start of the injury (Fox et al., 1993; Gokeler et al., 2001). An
example of an acute injury is an ankle sprain. Chronic injuries repeat themselves
due to continued tennis play or the lack of proper rehabilitation (Fox et al., 1993;
Gokeler et al., 2001). An example of a chronic injury would be a tennis elbow that
has been present for a year or two and flares up during long, gruelling
tournaments. Acute injuries are much easier to treat than chronic injuries and if
you take care of them initially, you can prevent them from becoming chronic (Roy
& Irvin, 1983; Roetert & Ellenbecker, 1998; Montalvan et al., 2002).
2.6.2 Occurrence of Tennis Injuries:
Analysis of epidemiological studies done in tennis (Table 13) shows a high
prevalence of shoulder and elbow injuries. According to this research, shoulder
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injuries ranges from 10% to 30% among elite junior tennis players, and 80% of all
tennis injuries are caused by overuse.
Table 13: Epidemiology of upper extremity overuse injuries in tennis players.
Population
Age
Sample
Incidence
(years)
size
(%)
Reference
Shoulder:
•
Elite juniors
11-14
97
14
Kibler et al., 1988
•
Elite juniors
16-20
66
18
Reece et al., 1986
•
Elite juniors
12-19
-
24
Lehman, 1988
231
17
Priest et al., 1977
534
18
Hang & Peng, 1984
150
21
Kitai et al., 1986
Elbow:
•
Recreational
adults
•
Recreational
adults
•
Recreational
adults
It is important that the rehabilitation programme focuses on the relationship
between injuries within the upper extremity. In a study done on world-class tennis
players, 74% of men and 60% of women had an injury in the dominant arm that
affected their tennis game (Priest & Nagel, 1976; Brooks, 2001). In the research
done by Priest et al. (1980) they illustrated the interplay and the relationship
between overuse injuries in the upper extremity. They discovered that there was
a 63% higher incidence of shoulder injuries among tennis players with a history
of tennis elbow than among players without a history of tennis elbow. This
reinforces the concept of a rehabilitation programme that addresses the entire
upper extremity kinetic chain in the tennis player (Priest et al., 1980; Brooks,
2001; Rubin & Kibler, 2002; Schmidt-Wiethoff et al., 2003).
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2.6.3 Prevention of Shoulder Injuries:
As mentioned earlier, most of the injuries that occur in tennis are due to overuse.
The training programme and specific exercises are therefore very important in
order to minimize the risk of injury.
Due to the nature of tennis, for example, the intrinsic tendons get overloaded
from high-intensity decelerating and eccentric muscular contractions of the
posterior rotator cuff during the follow-through phase of the serve (Gokeler et al.,
2001; Schmidt-Wiethoff et al., 2003). This can lead to tendinous inflammation
and progress to an undersurface (articular side) rotator cuff tear if the muscles
are not strong enough (Ellenbecker, 1995; Gokeler et al., 2001). The rotator cuff
muscles are the primary muscles preventing the humerus head from slipping out
of the glenoid cavity during play and is active during all tennis strokes (Roetert &
Ellenbecker, 1998; Sullivan, 2001). Resulting from its repetitive muscle work, one
common shoulder injury is damage to the rotator cuff. The tendon becomes
inflamed due to the heavy workload of the tennis strokes. Tendons generally heal
slowly, because their blood supply and healing potential are less than those of
muscles (Roetert & Ellenbecker, 1998; Schmidt-Wiethoff et al., 2000; Sullivan,
2001; Ellenbecker et al., 2002).
Another very important factor that makes the tennis player vulnerable to overuse
injuries in the shoulder is muscle imbalance (Schmidt-Wiethoff et al., 2000;
Ellenbecker et al., 2002; Schmidt-Wiethoff et al., 2003). Typically in tennis
players, the anterior muscles of the shoulder and the chest (pectoralis and
anterior deltoids) are stronger than the rotator cuff and the upper back muscles
that support the scapula (Roetert & Ellenbecker, 1998). It is therefore very
important that the tennis training programme focuses on the strengthening of the
rotator cuff and the upper back muscles (Plancher et al., 1995; Roetert &
Ellenbecker, 1998; Ellenbecker et al., 2002).
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2.6.3.1 Precautions in strengthening the rotator cuff muscles:
i)
Avoid using heavy weights:
By using heavy weights while strengthening the rotator cuff muscles, the body
will be forced to use larger muscle groups, such as the trapezius and the deltoid.
Therefore it is recommended that the athletes use low-resistance, high-repetition
format in strengthening the rotator cuff muscle (Plancher et al., 1995; Roetert &
Ellenbecker, 1998; Kraemer et al., 2003).
ii)
Minimize the lifting of weights overhead:
In tennis, the shoulder is seldom lifted overhead, even on the serve. The
following six positions can be used to specifically train the rotator cuff muscles in
a save position. These positions are all demonstrated in the tennis specific
exercises in Chapter 2.7:
a. Prone horizontal abduction (p91);
b. 90º-90º external rotation (p93);
c. Scaption (empty can) (p93);
d. External shoulder rotation with rubber tubing (p94);
e. Internal shoulder rotation with rubber tubing (p95); and
f. External shoulder rotation with abduction (p96) (Roetert & Ellenbecker,
1998).
2.6.3.2
Sport-specific Training Programmes:
It is important that the training programme of the athlete is sport-specific. These
exercises will form the base for preventing injuries (Hay & Reid, 1999; Sullivan,
2001).
Additional preventative tennis specific exercises that will reduce the risk of injury,
are discussed in Chapter 2.7.
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2.6.4 Rehabilitation of the Injured Shoulder:
Thorough understanding of the biomechanical stresses and anatomical
adaptations in tennis players can enhance diagnosis and treatment of these
injuries (Ellenbecker, 1995; Ellenbecker et al., 2002). The formulation of a
comprehensive rehabilitation programme that focuses on the upper extremity
kinetic chain, serves to restore normalized joint arthrokinematics and enables a
full return to the repetitive musculoskeletal demands of tennis (Ellenbecker,
1995; Soderberg, 1997; Meister, 2000; Ellenbecker et al., 2002).
Until recently, the role of the scapula in the clinical evaluation and rehabilitation
of the shoulder and upper extremity disorders has received very little attention.
Research shows that it is important to diagnose and treat the shoulder in the
context of the kinetic chain (Soderberg, 1997; Rubin & Kibler, 2002). A kinetic
chain is a series of links and segments activated sequentially in a co-ordinated
fashion in order to generate and transmit forces to accomplish a specific function
(Feltner & Dapena, 1989; Dillman, 1990; Ellenbecker et al., 2002; Rubin & Kibler,
2002;). In activities that involve a throwing action, like tennis, there is an openended kinetic chain with proximal-to-distal muscle activation and co-ordination of
body segments that produces interactive movements at the terminal segment
(wrist and hand) (Rubin & Kibler, 2002). In the throwing motion, the sequence of
link activation begins with the creation of a ground reaction force as a result of
the foot and leg pushing against the ground. This force is then dramatically
increased as it is transmitted through the knees and the large muscles of the
legs, through the hips and into the lumbopelvic region and the rest of the trunk.
The proximal segments, the legs and the trunk, produce half of the energy (51%)
and force (54%) that is ultimately delivered to the distal end of the kinetic chain
(Atwater, 1971; Rubin & Kibler, 2002; Schmidt-Wiethoff et al., 2003). The scapula
and the glenuhumeral joint function both as a link and a segment in the kinetic
chain, rather than in isolation. They act to increase the kinetic energy and force
generated to the distal segments where the smaller muscles can position the arm
and the hand in order to control the throw. This activation sequence allows for
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proximal stability and distal mobility in the active kinetic chain (Meister, 2000;
Ellenbecker et al., 2002; Rubin & Kibler, 2002). According to Rubin & Kibler
(2002) a kinetic chain varies with the position and the environment in which the
activity is being performed. The activities can generally be divided into two
categories:
•
Sitting versus standing; and
•
Land-based versus water-based.
When an individual reaches, pushes or pulls from a sitting position, there is less
energy and force contributed by the legs than executing force from a standing
position. The primary generator for the upper extremity motion is the initiation of
trunk stabilization (Rubin & Kibler, 2002; Schmidt-Wiethoff et al., 2003). In the
case of aquatic sports, there are also additional considerations that are important
in evaluating the symptoms of the shoulder and also during the rehabilitation
process (Atwater, 1971; Ellenbecker et al., 2002; Schmidt-Wiethoff et al., 2003 ).
2.6.4.1
Physical Examination of the Shoulder:
It is important to perform the evaluation in the context of the kinetic chain in order
to elucidate functional deficits that are related to patho-anatomy, pathophysiology or patho-mechanics (MacDougall et al., 1991). The evaluation must
be complete and specific about the primary diagnosis that may be causing
secondary symptoms. An example is that rotator cuff tendonitis may be caused
by either instability due to capsular laxity or abnormal scapular mechanics
(MacDougall et al., 1991; Schmidt-Wiethoff et al., 2000; Rubin & Kibler, 2002). In
order to accomplish this, the clinician must take an accurate history, evaluate
alterations in local and distant anatomy, scapular mechanics, and kinematics of
the entire kinetic chain (Rubin & Kibler, 2002).
While discussing the clinical history, the following aspects of the shoulder should
be observed:
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i. The patient’s posture:
This includes:
•
The position of the neck and head, trunk and the shoulders. Postural
alignment can further be assessed by applying an axial load on top of the
shoulders while the patient attempts to prevent accentuation of lumbar
lordosis. (Schmidt-Wiethoff et al., 2000; Ellenbecker et al., 2002; Rubin &
Kibler, 2002);
•
Lumbopelvis stability and strength. These are evaluated with a modified
Trendelenberg test where the patient is asked to balance and squat,
standing on each leg independently (Sullivan, 2001); and
•
Trunk strength. This is determined by having the patient in a supine
position, lowering each leg from an elevated position while attempting to
prevent lumbar lordosis (MacDougall et al., 1991; Rubin & Kibler, 2002).
ii.
Scapulohumeral Rhythm:
This is observed from behind as the patient slowly raises and lowers the arms
in abduction and flexion. By doing this, the concentric and eccentric function
of the scapular stabilizers can be assessed. Weakness is frequently seen
during the eccentric phase (Gokeler et al., 2001; Rubin & Kibler, 2002).
There are three distinct patterns of scapular dyskineses that are commonly
observed:
Type I: Winging occurs at the inferior medial border;
Type II: This involves the entire medial border of the scapula; and
Type III: The superior medial border is prominent (Kibler et al., 2003).
To date, no reproduceable association between specific shoulder pathological
diagnoses and specific dyskinesis patterns has been seen (Meister, 2000;
Ruben & Kibler, 2002).
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iii.
Glenohumeral range of motion:
This range of motion must be observed to document all abnormal movements
of the scapula during internal and external rotation at 90º of abduction. If any
pain occurs during abduction or forward flexion, the examiner must attempt to
correct the problem by substituting for the lower trapezius while inhibiting the
upper trapezius. This test is called the scapular assistance test (SAT) and is
considered positive if the pain is eliminated or significantly reduced by this
manoevre. A positive SAT- test is an indication of proximally derived
dyskinesis with secondary subacromial impingement (Kibler, 1998; SchmidtWiethoff et al., 2000; Rubin & Kibler, 2002).
iv.
Scapular positioning:
The lateral scapular slide test can be used as a static measurement to
determine scapular positioning (Kibler, 1998; Sullivan, 2001). This test
involves measuring the side-to-side difference from the spinous process of
the seventh thoracic vertebra to the infero-medial border of the scapula in the
following three positions:
•
Position 1: With the arms at the sides;
•
Position 2: With the hands on the pelvic rim; and
•
Position 3: With the arms in 90º abduction with the shoulders
internally rotated and the forearms pronated.
A difference of 1,5cm is considered as clinically significant (Rubin & Kibler,
2002; Sullivan, 2001).
v.
Testing of the rotator cuff:
The muscles of the rotator cuff can be tested manually with:
•
Resisted external rotation in adduction and 90º of abduction for the
infraspinatus and the teres minor;
•
Resisted elevation in the scapular plane for the supraspinatus; and
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•
The Napoleon test for the subscapularis (Gokeler et al., 2001;
Burkhart & Tehrany, 2002; Ellenebecker et al., 2002; Montalvan et al.,
2002).
If significant weakness occurs either with or without associated pain, the test
should be repeated with repositioning of the scapula (Burkhart & Tehrany,
2002; Rubin & Kibler, 2002).
vi. Lesions of the superior labrum:
A passive distraction test can be used to assess the integrity of the superior
labral attachment to the glenoid (Figure 19) (Rubin & Kibler, 2002).
Figure 19: Passive distraction test. (a) Arm is positioned overhead in the
plane of the trunk, the elbow is extended and the forearm in neutral or slight
supination. (b) Forearm is gently pronated (Rubin & Kibler, 2002).
In this passive distraction test, the patient is placed in the supine position with
the shoulder off the examining table, the arm is flexed overhead in the plane
of the trunk with the elbow extended, and the forearm is held in a neutral
position or in slight supination. The forearm is then gently pronated without
rotation of the humerus. If pain is elicited, it is an indication of the anterior and
posterior locations of the lesion (Burkhart & Tehrany, 2002; Rubin & Kibler,
2002).
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vii. Labral pathology:
Labral pathology is diagnosed by assessing clicks and grinds that are
associated with rotation and capsular loading, joint-line palpation, modified
Jobe relocation test (apprehension suppression test), and the Mayo shear
test, which is specifically for posterior superior labral abnormality, or internal
impingement (Rubin & Kibler, 2002). Alteration of posterior pain, in the
position of the throwing arm, with the arm 90º abducted and 90º externally
rotated, by scapular retraction and depression is also an indication of
posterior superior labral pathology (Burkhart & Tehrany, 2002).
viii. Capsular laxity and instability:
Capsular laxity and instability can be evaluated with the load and shift test in
the anterior, posterior and inferior directions with varying degrees of rotation
and
elevation.
Anterior
and
posterior
apprehension,
apprehension
suppression and also pain associated with the relocating testing can be
noted. (Burkhart & Tehrany, 2002; Rubin & Kibler, 2002; Wright & Matava,
2002). The examiner should be aware of the fact that capsular laxity varies
with age, chosen activity of sport, temporal relationship with the last workout
and in some cases the dominant arm. Normal variances in capsular laxity
must be borne in mind (Rubin & Kibler, 2002; Wright & Matava, 2002).
Harryman et al. (1992) reported anterior and posterior translation of almost
8mm both anteriorly and posteriorly in asymptomatic volunteers.
2.6.4.2
Principles of Functional Rehabilitation:
The goal of functional rehabilitation is to restore normal function instead of just
eliminating the symptoms. It is based on the basic principles of the kinetic chain,
with restoration of normal anatomy, physiology, biomechanics and kinematics
(Kibler & Livingston, 2001). Research done by Hodges (1999) showed that
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before either arm or leg movement is initiated, the transversus abdominus is
activated first. This increases the intra-abdominal pressure in anticipation of the
action. It is important that, during the initial phase of rehabilitation, the distant
deficits should be corrected first. This also involves the restoration of flexibility
and strength in the hip, trunk and the periscapular regions (Rubin & Kibler, 2002).
Local deficits, such as a shortened pectoralis minor or subscapularis muscletendon unit, should be corrected within the patient’s tolerance (Hodges, 1999;
Kibler & Livingston, 2001).
Control of the proximal segments of the kinetic chain should be accomplished
during the early stages of rehabilitation. The process of restoration of normal
posture, hip and trunk extension and scapular retraction should be achieved in
an upright position with the feet on the ground in order to restore normal
physiology and proprioception (Rubin & Kibler, 2002). Thus, all exercises should
be initiated with the patient in the “ideal position”. This includes good postural
alignment, a level pelvis, and the scapula retracted and depressed. Sequential
distal segment activation is then facilitated with those exercises that connect the
hip and the trunk with the scapula, and the scapula with the rotator cuff (Hodges,
1999; Kibler & Livingston, 2001; Rubin & Kibler, 2002).
As proximal stability is being regained, rehabilitation of the scapula should be
incorporated. This includes scapular retraction and depression in order to restore
the normal force couples, and thereby:
1. decreasing acromial tipping;
2. providing a stable muscle base for shoulder function;
3. positioning the glenoid for optimal stability and rotator cuff function; and
4. enabling the scapula to funnel and transmit the forces from the trunk to
the upper extremity as part of the kinetic chain (Burkhart & Tehrany, 2002;
Rubin & Kibler, 2002).
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Once the scapula is normal, glenohumeral rehabilitation can proceed. This
includes the restoration of capsular mobility and rotator cuff activation to restore
normal compression (Burkhart & Tehrany, 2002). As soon as the patient can
isolate the specific rotator cuff muscles, rehabilitation should be integrated into
the context of the kinetic chain. In order to decrease the shear forces on the joint
while enhancing strength gains, it is recommended that closed-chain exercise
protocols be used (Kibler & Livingston, 2001; Rubin & Kibler, 2002).
Finally, plyometric exercises involving all kinetic-chain segments are incorporated
in the final phase of rehabilitation. These exercises will then restore the required
power and activate stretch-shortening cycles as soon as there is appropriate
anatomical healing, satisfactory range of motion and when the integrity of the
kinetic chain has been restored (Hodges, 1999; Rubin & Kibler, 2002).
2.6.4.3
Guidelines for Core-based Functional Rehabilitation:
1. Proximal stability must be regained before distal mobility is sought.
2. The focus should be on scapular position and control, with tightened
abdominal muscles that holds the spine in a neutral position, and correct
postural alignment.
3. The patient must be able to identify and isolate the specific muscles to be
strengthened.
4. Muscle groups should be trained in a co-ordinated, synchronized pattern to
re-establish the force couples for scapular stabilization and elevation in order
to control pain, decrease subacromial impingement and to facilitate muscle
re-education.
5. Exercises should be relatively pain free. It is very difficult to progress a painful
joint. If pain occurs during rehabilitation, it is a sign that either the wrong
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exercises are being done at that time in the recovery process or the exercise is
being done incorrectly.
6. The quality of the exercise is more important than the quantity being
performed. The patient should therefore focus more on muscle control than on
the number of repetitions being done.
7. Exercises should be done until the muscle fatigues. This is the point at which
biomechanics become abnormal, and it is better to stop rather than to do the
remaining repetitions incorrectly.
8. The progression in the strengthening programme is isometric to eccentric to
concentric training.
9. Closed-chain exercises always preceed open-chain exercises.
10. As more progressive exercises are added, the easier ones should be
eliminated to prevent boredom on the part of the patient.
(Scripture et al., 1894; Scripture et al., 1897; Hellebrandt et al., 1950;
Hellebrandt & Waterland, 1962; Stromberg, 1986; Kibler & Livingston, 2001;
Rubin & Kibler, 2002; Roetert, 2003; Schmidt-Wienhoff et al., 2003)
2.6.4.4
Phases of Rehabilitation:
The recovery phase can be divided into early and late segments to allow for
varied goals in this prolonged period of rehabilitation (Rubin, 2000; Kibler &
Livingston, 2001).
i)
Acute Phase:
This phase is relatively short and in the postoperative patient it ranges from
approximately 1 to 3 weeks. The goals are to:
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•
control the pain and inflammation by means of immobilization, modalities,
analgesics and non-steroidal anti-inflammatory drugs (Kibler & Livingston,
2001);
•
clear soft tissue restrictions and postural abnormalities with soft tissue
mobilization and stretching (Rubin, 2000; Rubin & Kibler, 2002);
•
begin muscle re-education with postural- and core strengthening
exercises. This includes lumbopelvic stabilization, scapular positioning
(retraction and depression), and also closed-chain rotator cuff exercises
(Kibler & Livingston, 2001; Rubin & Kibler, 2002); and
•
begin active and active-assisted range of motion exercises, starting in the
scapular plane or forward flexion (Rubin, 2000; Rubin & Kibler, 2002).
The criteria used to advance from the acute phase to the early recovery phase
are as follows:
•
minimal pain on range of motion;
•
reasonable lumbopelvic strength;
•
adequate scapular control;
•
adequate soft-tissue healing; and
•
adequate release of soft-tissue restrictions (Rubin & Kibler, 2002;
Sonnery-Cottet et al., 2002).
ii)
Early Recovery Phase:
This phase usually lasts for 3 to 6 weeks post-operatively, and the goals are to:
•
increase range of motion and flexibility with passive range of motion
exercises and joint mobilization as well as active-assisted and active
range of motion exercises;
•
increase strength, control and endurance; and
•
restore the normal kinematics (Rubin, 2000; Rubin & Kibler, 2002;
Sonnery-Cottet et al., 2002).
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The criteria used to advance from the early recovery phase to the late recovery
phase are as follows:
•
pain-free range of motion;
•
almost the full range of motion and flexibility;
•
improved strength and control; and
•
improved kinematics (Rubin & Kibler, 2002; Sonnery-Cottet et al.,
2002).
iii)
Late Recovery Phase:
This phase usually extends from 6 to 12 weeks post-operatively, and the goals
are to:
•
restore the full range of motion and flexibility with joint mobilization, soft
tissue work, and stretching in all planes;
•
increase strength, power and endurance with exercises that stress the
core-based muscle synergy; and
•
advance eccentric and concentric scapular stabilization exercises (Rubin,
2000; Sullivan, 2001; Rubin & Kibler, 2002; ).
The criteria used to advance from the late recovery phase to the functional
phase are as follows:
•
full range of motion;
•
normal kinematics; and
•
approximately 75% of the normal strength, power and endurance
(Sullivan, 2001; Rubin & Kibler, 2002).
iv)
Functional Phase:
This phase usually begins 3 months post-operatively. In this phase it is wise to
take advantage of the knowledge and the skills of coaches and trainers in the
development of sport-specific progressions. The goals are to:
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•
restore the sport and work specific kinematics;
•
increase strength, power, and endurance to a functional level for the
chosen activity of the patient; and
•
restore the required activity-specific co-ordination, speed and quickness
(Rubin, 2000; Burkhart & Tehrany, 2002; Rubin & Kibler, 2002).
During this functional phase, plyometric exercises, drills for agility and coordination, and also conditioning exercises that are specific for the patient’s
chosen sport or activity are pursued (Hodges, 1999; Rubin & Kibler, 2002).
For the patient to advance from this phase, the patient must have:
•
normal upper quarter kinematics within the context of the kinetic chain;
•
a normal range of motion and flexibility for the specific sport or activity;
•
approximately 90% strength; and
•
symptom-free activity or sport-specific drills (Sullivan, 2001; Rubin &
Kibler, 2002; Roetert, 2003).
2.7 TENNIS SPECIFIC SHOULDER EXERCISES
2.7.1 Rotator cuff programme:
As mentioned earlier, the rotator cuff plays an important role in tennis and it is
therefore very important to strengthen all these muscles (Meister, 2000; SchmidtWiethoff et al., 2000; Montalvan et al., 2002). The following exercises are used to
develop the rotator cuff muscles. It is recommended that these exercises be
initially performed with a 0.5 to 1.0kg weight, because these muscles are very
small. Also, start with two to three sets of 12 to 15 repetitions to promote
endurance to these muscles first. If a weight is used that is too heavy, the player
may compensate and perform the exercises using the larger muscles groups that
are already developed (Roetert & Ellenbecker, 1998; Montalvan et al., 2002).
According to Roetert & Ellebecker (1998) even the strongest and the largest
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athletes use a maximum of 2 to 2.5kg for these exercises strengthening the
rotator cuff muscles.
a.
Prone horizontal abduction: (Figure 20)
Focus:
Strengthens the rotator cuff, rhomboids, trapezius and the posterior
deltoids.
Start:
Lie on the stomach on a table with the racket arm hanging straight
down towards the floor with the thumb pointing outwards.
Action:
Raise the arm outwards to the side at a 90º angle until almost
parallel to the floor. Lower it back to the starting position and repeat
(Roetert & Ellenbecker, 1998; Burkhart & Tehrany, 2002).
(a)
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(b)
Figure 20: Prone horizontal abduction. (a) Starting position. (b) Action (Roetert &
Ellenbecker; 1998).
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b.
90º-90º External shoulder rotation: (Figure 21)
Focus:
Develops the external rotators of the shoulder.
Start:
Kneel and place the arm on an incline bench. Keep the upper arm
parallel to the ground and the forearm perpendicular to the upper
arm at 90º.
Action:
Maintain a right angle at the elbow and externally rotate the forearm
until it points to the ceiling at 90º abduction. Slowly lower the arm
and return to the starting position (Roetert & Ellenbecker, 1998;
Burkhart & Tehrany, 2002; Montalvan et al., 2002).
(a)
(b)
Figure 21: 90º-90º External shoulder rotation. (a) Starting position. (b) Action
(Roetert & Ellenbecker, 1998).
c.
Scaption (Empty Can): (Figure 22)
Focus:
Strengthens the supraspinatus muscle and the deltoid.
Start:
Stand with the elbow straight and the thumb pointing towards the
ground.
Action:
Raise the arm up to shoulder level on a diagonal plane, 30º - 45º to
the side. Slowly lower the arm and repeat.
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Note: Be sure not to raise the arm above shoulder height (Roetert
& Ellenbecker, 1998).
Figure 22: Scaption (Empty Can). (a) Starting position. (b) Action (Roetert &
Ellenbecker, 1998).
d.
External shoulder rotation with rubber tubing: (Figure 23)
Focus:
Develops external rotator strength of the shoulder.
Start:
Secure the rubber tubing at waist height to a doorknob. Stand
sideways to the door with the racket arm furthest from the door.
Place a small, rolled towel under the racket arm and squeeze.
Action:
Hold the rubber tubing in the racket hand and start with this hand
close to the stomach. Rotate the hand and the forearm away from
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the stomach until the hand and forearm are straight out in front of
the elbow, pulling the tubing for resistance. Return the arm to the
starting position and repeat. The elbow must be kept at a 90º-angle
throughout the exercise (Roetert & Ellenbecker, 1998; Burkhart &
Tehrany, 2002; Montalvan et al., 2002).
Figure 23: External shoulder rotation with rubber tubing. (a) Starting position. (b)
Action (Roetert & Ellenbecker, 1998).
e.
Internal shoulder rotation with rubber tubing:
Focus:
Develops internal rotator strength of the shoulder.
Start:
Secure the rubber tubing at waist height to a doorknob. Stand
sideways to the door with the racket hand closest to the door. Place
a small, rolled towel under the racket arm and squeeze.
Action:
Grip the rubber tubing in the racket hand and start with the arm and
forearm in a 90º-angle straight out in front of the elbow. Rotate the
hand and forearm in towards the stomach. Return to the starting
position and then repeat. The elbow must be kept at a 90º-angle
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throughout the exercise (Roetert & Ellenbecker, 1998; Ellenbecker
et al., 2002).
f.
External shoulder rotation with abduction: (Figure 24)
Focus:
Strengthens the rotator cuff in a position specific to the tennis
serve.
Start:
Secure the rubber tubing at waist height to a doorknob. Stand
facing the door with the shoulders abducted to 90º, about 30º in
front of you on a diagonal. Use the opposite hand to support the
upper arm.
Action:
Grip the tubing in the racket hand and rotate the hand back until it
reaches nearly vertical. Return to the starting position and then
repeat (Roetert & Ellenbecker, 1998; Burkhart & Tehrany, 2002).
Figure 24: External shoulder rotation with abduction (Roetert & Ellenbecker,
1998).
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2.7.2 Additional tennis specific upper body exercises:
a.
Seated row: (Figure 25)
Focus:
To develop the rhomboids, trapezius, posterior deltoids and the
biceps.
Start:
Sitting position with the knees slightly flexed and the hands holding
onto a cord or band device, cable column or a seated row machine.
Action:
Keep the upper body erect and avoid leaning backwards. Then pull
the band handles toward the chest and the upper abdomen area
while keeping the elbows close to the sides. Return slowly to the
start position and then repeat the action (Roetert & Ellenbecker,
1998; Burkhart & Tehrany, 2002; Ellenbecker et al., 2002).
Figure 25: Seated row (Roetert & Ellenbecker, 1998).
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b.
Bent over row:
Focus:
Strengthens the latissimus dorsi, rhomboids, trapezius and the
posterior deltoids.
Start:
Bend over a bench with the non-active knee and hand supporting
on the bench. Keep the back flat and supported by tightening the
abdominal muscles and the buttocks.
Action:
Start by holding the dumbbell in the hand with the arm fully
extended below the shoulder. Lift the dumbbell by raising the elbow
to the ceiling until the dumbbell touches the side of the abdomen
(Roetert & Ellenbecker, 1998; Burkhart & Tehrany, 2002).
c.
Push-ups:
Focus:
General conditioning and strengthening of the upper body.
Start:
The hands are placed shoulder-width apart with the body in a
straight line from the toes to the head.
Action:
Slowly lower the body down until the upper arm is parallel to the
ground. Push upward until the elbows are completely straight and
round the back outward like a cat. The rounding motion at the end
of the push-up is very important for it increases the work by the
muscles that stabilize the scapula (Roetert & Ellenbecker, 1998;
Ellenbecker et al., 2002).
Note: If a player has a history of shoulder problems or experience any
shoulder pain, only lower the body one-half of the way down.
d.
Lat pull down:
Focus:
Strengthens the latissimus dorsi and the bicep muscles.
Start:
Use either a lat pull down machine, overhead cable or rubber
tubing. Reach upward and grasp the handles with a wide grip.
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Action:
Pull the bar, cable or tubing down by bringing the bar in front of the
head toward the middle of the chest. Slowly return the bar to the
starting position and repeat (Roetert & Ellenbecker, 1998).
e.
Chest press:
Focus:
Strengthens the pectoralis major and pectoralis minor, serratus
anterior, triceps and the anterior deltoids.
Start:
Lie on your back on a narrow bench with the arms externally
rotated at a 90º-angle to the torso.
Action:
Keep the wrist directly over the elbows without locking the elbows
and then extend the hands upwards toward the ceiling. While the
hands extends upward, round the shoulders by pushing the hands
as far as possible away from the body. This extra motion works the
serratus anterior muscle, which supports the scapula while playing
tennis (Roetert & Ellenbecker, 1998; Ellenbecker et al., 2002;
Roetert, 2003).
f.
Biceps curl:
Focus:
Strengthens the bicep brachi, brachialis and the brachioradialis.
Start:
Stand with the feet shoulder width apart while holding the dumbbell
with the hands supinated.
Action:
Keep the elbows at the sides while bringing the weights upwards
towards the shoulders. Make sure not to arch the back or to lean
backwards during this exercise. Slowly lower the hands to the
starting position, making sure not to hyperextend or to lock the
elbows (Roetert & Ellenbecker, 1998; Burkhart & Tehrany, 2002).
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g.
Triceps extension:
Focus:
Strengthens the triceps muscle.
Start:
Lie in a supine position holding a dumbbell in the hand with the
shoulder and elbows bent 90º. Use the other hand to support the
upper arm and to keep it still throughout the exercise.
Action:
Straighten the elbow by raising the hand and the weight upward
and make sure that the elbows do not lock (Roetert & Ellenbecker,
1998; Burkhart & Tehrany, 2002; Roetert, 2003).
h.
Shoulder shrugs:
Focus:
Develops the upper trapezius and the scapula stabilizers.
Start:
In a standing position, keep the feet shoulder width apart, arms at
the sides and holding the dumbbells in the hands.
Action:
Keep the arms at the sides, raise the shoulders upward towards the
ears and squeeze the scapulas together while rolling the shoulders
backwards. Return to the starting position by slowly lowering the
shoulders and then repeat (Roetert & Ellenbecker, 1998;
Ellenbecker et al., 2002).
i.
Shoulder punches:
Focus:
Strengthens the serratus anterior, which is an important scapula
stabilizer.
Start:
In a supine position, keep the shoulder flexed to 90º and the elbow
straight. Hold a medicine ball or a dumbbell in line with the
shoulder.
Action:
Keep the elbow straight and raise the hand toward the ceiling as far
as possible. Slowly return the hand to the starting position and
repeat. The hand should only move about 15cm up and down
(Roetert & Ellenbecker, 1998; Roetert, 2003).
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j.
Prone fly:
Focus:
Works the upper deltoid, rhomboids and trapezius.
Start:
Lie in a prone position on a narrow bench with the feet off the
ground.
Action:
With a dumbbell in both hands, extend the arms from the sides at a
right angle (90º). Maintain the right angle at the shoulders while
raising the arms until they are nearly parallel to the ground (Roetert
& Ellenbecker, 1998; Burkhart & Tehrany, 2002).
2.7.3 Forearm and Wrist Programme:
a.
Wrist Curls: (Figure 26)
Focus:
Works the wrist and finger extensors.
Start:
Sit down on a chair with the elbow flexed and the forearm resting
on a table or over the knee. With the palm facing downwards, let
the wrist and the hand hang over the edge.
(a)
(b)
Figure 26: Wrist Curls. (a) Starting position. (b) Action (Roetert & Ellenbecker,
1998).
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Action:
Slowly curl the wrist and the hand upwards while the opposite hand
stabilizes the forearm. Make sure that only the wrist is moving and
not the elbow. Raise the hand slowly, hold for 2 seconds and then
slowly lower the weight again and repeat (Roetert & Ellenbecker,
1998; Burkhart & Tehrany, 2002; Roetert, 2003).
b.
Wrist Curls: Flexors: (Figure 27)
Focus:
Strengthens the wrist and the finger flexors.
Start:
Sit down on a chair with the elbows flexed and the forearm resting
on a table or over the knee. With the palm facing upwards, let the
wrist and the hand hang over the edge.
Action:
Slowly curl the wrist and the hand upward while the opposite hand
stabilizes the forearm. Make sure that only the wrist is moving and
not the elbow. Raise the hand slowly, hold for 2 seconds and then
slowly lower the weight again and repeat (Roetert & Ellenbecker,
1998; Ellenbecker et al., 2002).
Figure 27: Wrist Curls: Flexors (Roetert & Ellenbecker, 1998).
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c.
Forearm pronation:
Focus:
Strengthens the forearm pronators.
Start:
Sit down on a chair with the elbow flexed and the forearm resting
on a table or over the knee. Let the wrist and the hand hang over
the edge of the table or knee. Use a dumbbell with a weight at only
one end and start the exercise with the palm facing upwards and
the handle horizontal.
Action:
Slowly raise the weight by rotating the forearm and the wrist to a
vertical position (Roetert & Ellenbecker, 1998; Burkhart & Tehrany,
2002).
d.
Forearm supination: (Figure 28)
Focus:
Strengthens the forearm supinators.
Start:
Sit down on a chair with the elbow flexed and the forearm resting
on a table or over the knee. Let the wrist and the hand hang over
the edge of the table or knee. Use a dumbbell with a weight at only
one end and start the exercise with the palm facing downwards.
Action:
Slowly raises the weight by rotating the forearm and the wrist to a
vertical position. Hold this position for 2 seconds and slowly return
to the starting position (Roetert & Ellenbecker, 1998; Burkhart &
Tehrany, 2002).
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(a)
(b)
Figure 28: Forearm supination. (a) Starting position. (b) Action (Roetert &
Ellenbecker, 1998).
e.
Radial deviation:
Focus:
Strengthens the muscles that stabilize the wrist in tennis.
Start:
Stand with the arm at the side and hold a dumbbell with a weight on
only one end. The end with the weight must be in front in the
neutral position with the thumb pointing straight ahead.
Action:
Slowly raise the weight and then lower it through a comfortable
range of motion. All the movement must be in the wrist with no
elbow or shoulder joint movement (Kraemer et al., 1995; Roetert &
Ellenbecker, 1998; Roetert, 2003).
f.
Ulnar deviation: (Figure 29)
Focus:
Strengthens the muscles that stabilize the wrist in tennis.
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Start:
Stand with the arm at the side and hold a dumbbell with a weight on
only one end. The end with the weight must be behind the body in
the neutral position with the thumb pointing straight ahead.
Action:
Slowly raise the weight and then lower it through a comfortable
range of motion. All the movement must be in the wrist with no
elbow or shoulder joint movement (Roetert & Ellenbecker, 1998;
Burkhart & Tehrany, 2002).
(a)
(b)
Figure 29: Ulnar deviation. (a) Starting position. (b) Action (Roetert &
Ellenbecker, 1998).
g.
Grip strengthening:
Focus:
Strengthens the forearm, wrist and the hand muscles that is used in
gripping the racket in tennis.
Start:
Start with the elbow bent at 90º at the side. Hold either a tennis or
squash ball, or putty in the palm of the hand.
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Action:
Squeeze the ball or the putty as hard as possible and hold that
position for three to five seconds. Release the pressure and then
repeat until the hand muscles feel fatigue. Increase the intensity of
this exercise by keeping the elbow straight (Kraemer et al., 1995;
Ellenbecker et al., 2002).
2.7.4
Plyometric Medicine Ball Program for the Shoulders
These plyometric exercises help to develop power in the upper body (Chu,
1995). A medicine ball is used for resistance and it requires explosive movement
patterns. For shoulder strengthening exercises, balls 2 to 3kg are used. In order
to reduce the risk of injuries, it is recommended to start with 2kg ball and then
gradually increases the load as the workout becomes easier. When you can
perform more than 50 repetitions without fatigue, the weight of the ball should be
increased (Kraemer et al., 1995; Turner & Dent, 1996).
a.
Chest Pass:
Focus:
Develops the pectoralis, triceps and the scapular stabilizers.
Start:
Stand 5m from a partner and hold the ball in front of the chest.
Action:
Pass the ball straight to the partner. The partner should try to “catch
and release” the ball as quickly as possible (Turner & Dent, 1996).
b.
Overhead Toss:
Focus:
Strengthens the latissimus dorsi and the triceps muscles.
Start:
Stand 2.5 to 3m away from a partner and hold the ball directly over
the head.
Action:
Toss the ball to the partner. The partner should try to “catch and
release” the ball overhead as quickly as possible (Kraemer et al.,
1995; Turner & Dent, 1996).
c.
Forehand Toss:
Focus:
Strengthens the muscles that are used in playing the forehand.
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Start:
Stand 2.5 to 3m away from a partner and hold the ball with both
hands on the forehand side.
Action:
Step and turn the same way as when playing a forehand taking the
ball back like a racket. By mimicking a forehand crosscourt
groundstroke, pass the ball to the partner. The partner must try to
“catch and release” the ball as quickly as possible by performing
the same forehand action (Chu, 1995; Kraemer et al., 1995).
d.
Backhand Toss:
Focus:
Strengthens the muscles that are used in playing a backhand.
Start:
Stand 2.5 to 3m away from a partner and hold the ball with both
hands on the backhand side.
Action:
Step and turn the same way as when playing a backhand taking the
ball back like a racket. By mimicking a backhand crosscourt
groundstroke, pass the ball to the partner. The partner must try to
“catch and release” the ball as quickly as possible by performing
the same backhand action (Kraemer et al., 1995; Turner & Dent,
1996).
2.8
POSTURAL DEVIATIONS
Due to the early involvement in competitive sport, children are often exposed to
types of stress that can affect the growth and development of their maturing
musculoskeletal systems in an adverse way (Skrzek, 2003). This can lead to a
disruption of the normal growth pattern. The most serious of all the growth
disorders is scoliolis, due to the fact that the body may disform and then inhibit
normal bodily organ function (Becker, 1986; Walker, 2003).
2.8.1 Scoliosis:
The vertebral curvature that is defined as scoliosis can be broadly categorized
as structural or functional (Smith, 2003). Portillo et al. (1982), Willner (1984),
Carlson (2003) and Smith (2003) describe structural curvatures as a deviation
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of over 10 degrees, accompanied by rotation. This definition specifies the
inclusion of bone and ligament malfunction as a criterion for structural torsion
that is associated with lateral curvature. Keim (1982) referred to functional
scoliosis as a “mild” form of vertebral disorder. It is not necessary to correct this
condition by an external device, but rather by side bending exercises (Katz,
2003; Milan, 2003). Tachdjian (1972), Katz (2003) and Walker (2003) noted
that functional scoliosis has generally got a single long thoracolumbar curve
with a predominately left convexity. Their research indicates that functional
scoliosis produces little rotation of the vertebral body with accompanying rib
deformity. This is a serious secondary complication of idiopathic scoliosis
(Smith, 2003). A characteristic of functional sciliosis is that the curve will
disappear during recumbency and suspension, and that the spine bends
equally well to both sides on lateral flexion of the trunk, with rotation to both
sides being equal (Becker, 1986; Skrzek, 2003; Smith, 2003).
2.8.1.1
Incidence of Scoliosis:
Idiopathic structural scoliosis is normally low among the normal population,
but notably higher among adolescents (Carlson, 2003; Katz, 2003). The
following research shows the occurrence of scoliosis:
Î Shands & Eisberg (1969) and Walker (2003) found that 1.9% or
approximately 1 000 subjects out of 50 000 adolescents to have scoliosis;
Î Avikainen & Vaherto (1983) and Katz (2003) reported scoliosis in 3 to 16%of
the population, depending on the degree of the curvature that has been
chosen as the limit, and on the age of the subject;
Î Willner (1984)and Skrzek (2003) reported 0.35 to 13% as the incidence of
structural scoliosis; and
Î Eckerson and Axelgaard (1984) and Smith (2003) reported that ideopathic
scoliosis, with a lateral curvature of unknown etiology, comprises 75 to 80%
of all scoliosis in the United States.
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Studies focusing on the occurrence of scoliosis among men and women
showed the following:
Î Shands and Eisberg (1969) found a predominance of scoliosis among
women that is about 5 times as great as that found in the male population;
and
Î Avikainen and Vaherto (1983) reported that 90% of all cases of scoliosis,
that require treatment, appear amongst women. They also found that mild
scoliosis is observed to be nearly as frequent in boys as in girls.
Research on scoliosis among athletes indicates the following:
Î Kuprian (1982) and Smith (2003) found the average frequency of ideopathic
scoliosis in athletes to be 2%. He also postulated that the incidence of
functional scoliosis is notable among athletes that are participating in sports
that develop extreme torque in repetitive serving, throwing and volleying
motions, such as tennis; and
Î Krahl & Steinbruck (1978), Weinberg (1986) and Milan (2003) examined top
athletes over 4 and 5 year intervals. They found a 33.5% incidence of
functional scoliosis and a 1.6% incidence of ideopathic scoliosis .
2.8.1.2
Screening for Scoliosis:
The screening process includes observations with the athlete in the standing
position and then in the forward bending position. In the erect standing position,
observations should be made for asymmetries of the lateral contours of the
trunk, shoulders, scapulae, and the lateral deviation of the spinal process
(Figure 30) (Dendy et al., 1983; Becker, 1986; Smith, 2003; Walker, 2003).
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(a)
(b)
Figure 30: (a) and (b): Athletes screened for scoliosis were observed in the
standing position for asymmetries of the lateral contours of the trunk, shoulders
and the scapula.
In the forward bending position, the observed rib hump asymmetry is
considered to be the positive clinical finding for structural idiopathic scoliosis
(Katz, 2003).
2.8.1.3
Development of the Scoliotic Curvature:
Hauser (1937), Carlson (2003) and Skrzek (2003) found that an inability of the
musculature of the back to perform up to the requirements of the demand
would ordinarily produce an increase in all the normal curves of the spine. This
attributes to the functional adaptation of the spine, with a subsequent muscular
imbalance between the anterior and posterior structures, which is recognized
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as ‘poor posture’ (Katz, 2003). They also reported that if this imbalance is not
corrected, a lateral curve might develop, producing a compensatory structural
scoliotic development (Carlson, 2003; Skrzek, 2003). Carlson (2003) and
Skrzek (2003) concluded that whenever there is a decrease in the strength of
the structure of the back, a loss of capacity, or an increase on the demand
made on the back, such as overload, scoliosis would develop. Krahl and
Steinbruck (1978) and Milan (2003) noted that unilateral upper limb motion in
athletes is a torsional repetitive motion. This motion occurs in combination with
trunk rotation. Becker (1986) found a 100% occurrence of lateral curvature to
the side of the dominant hand. This supports the effect of muscular imbalance
as noted by Katz (2003) and Smith (2003) and the dominant arm strength as
noted by Yeater et al. (1981), Milan (2003) and Skrzek (2003).
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CHAPTER 3
METHODS AND PROCEDURES
3.1 METHODS
In this chapter we will discuss the methods and procedures used for the testing
of the subjects in this study.
3.1.1 Subjects:
The number of subjects that participated in this study was 42 tennis players all
aged between 14 and 18 years. Both males and females were used for the
purpose of this study. All the players were training at the South African Tennis
Performance Centre (SATPC) and the International Tennis Federation (ITF) at
the University of Pretoria. The individuals were well matched with regard to age,
mass, activity level and intensity of training (Table 14). They were all elite tennis
players, practising daily at the University of Pretoria and scheduled for standard
major tournaments throughout the year. All the subjects followed specific
exercise programmes, with the experimental group following an additional
programme five times a week based on certain scientific exercise principles. This
scientific programme focused on the prevention of shoulder injuries.
Each player completed a questionnaire on his or her tennis and medical history.
The players were then divided into a control group and an experimental group.
First, the males and females were separated. In each group, all players that had
a history of shoulder injuries or shoulder pain were numbered separately. Firstly,
the numbers of the players with a medical history from the male group were
thrown into a hat. The first number drawn went to group 1, where after the name
went back into the hat. If the same number was drawn again, it was just thrown
back into the hat. The next new number to be drawn went to group 2 and was
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then thrown back into the hat. This went on until all the numbers were drawn.
After the players with a medical history were divided, the remaining males were
divided in the same way. The same procedure was followed to divide the female
group. From this point further, no distinction was made between the males and
females throughout the period of evaluation and training.
Both groups completed a series of physical scientific tests, consisting of:
1. Posture analysis;
2. Body composition;
3. Flexibility tests;
4. Functional strength of the upper body; and
5. Isokinetic power and endurance of the shoulder muscles.
These tests were done every three months over a nine-month period and the
results of each battery of tests were used to upgrade the new programmes. The
experimental group did specific preventative shoulder exercises 5 times a week
in addition to their gymnasium programme twice a week, while the control group
followed a normal strengthening program twice a week. On the two days of
gymnasium work, the preventative exercises were incorporated into the
experimental group’s gymnasium programmes. A medical doctor evaluated all
kinds of muscle stresses or pains immediately throughout the research period. All
the injuries and muscular problems for both the control group and the
experimental group were documented carefully. At the end of the research period
the data was compared to determine the difference in injury occurrence between
the two groups, as well as the effect of a proper rehabilitation programme.
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Table 14: Subject data of all the tennis players taking part in this study.
EXPERIMENTAL AND CONTROL GROUP
X+/- SD
Experimental
Control Group
Group
Age
15,2 +/-1.6
15.6 +/-2.6
Body Weight
58.2 +/-8.5
59.7 +/-11.1
172.3 +/-10.7
170.4 +/-10.8
Fat Percentage
12.7 +/-2.7
12.8 +/-3.8
Muscle Percentage
42.7 +/-2.4
42.1 +/-5.6
Lean Body Mass
46.5 +/-8.1
47.8 +/-7.8
Height
The following inclusion criteria were used to determine the subject’s eligibility for
the study:
a. South African Tennis Performance Centre and International Tennis
Federation: All participants were to train at one of these two centres at the
University of Pretoria in order to control their training programmes both on
and off the tennis court;
b. Age: All the subjects were aged between 14 and 18 years;
c. Activity indices: The subjects were not allowed to do any gymnasium or other
high- intensity activities 48 hours prior to the tests; and
d. Conditioning programmes: The subjects were not allowed to do any additional
strengthening exercises throughout the research period but those prescribed
to them.
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3.1.2 Testing Environment:
All the tests were done inside the laboratory at the Institute for Sport Research at
the University of Pretoria. The temperature was measured at 21 degrees Celsius
and the Barometric pressure at 662mmHg. No tests were done out in the field
where wind and temperature could influence the results. It can thus be stated
that all tests were done in a controlled environment.
3.1.3 Testing Equipment:
The following equipment was utilized in the study:
a. The Harpenden Anthropometer was used to measure the subject’s standing
height and a model D2391 Detecto standing scale was used to measure
the total body weight.
Figure 31: Harpenden Anthropometer.
Figure 32: Model D2391 Detecto
standing scale.
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b. The Drinkwater Ross method was used to determine fat percentage at the
first and the last tests (Roy & Irvin, 1983). Equipment used for this method
were:
i.
Skinfold Caliper;
ii.
Steel retractable measuring tape; and
iii.
Wide-Spreading Calipers.
a
b
c
Figure 33: Equipment used for measuring body composition. (a) Skinfold caliper,
(b) Steel retractable measuring tape, and (c) Wide-Spreading Caliper.
c. A black pen and measuring tape were used to determine whether scoliosis
was present.
d. A back evaluation door was used to determine the difference in shoulder
and hip height (Figure 34).
e. A protractor was used to determine flexibility of the shoulder’s internal and
external rotators.
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f. Steel retractable measuring tape and a stick were used to determine
shoulder flexibility.
Figure 34: Back evaluation door.
g. A stopwatch was used to measure functional strength and endurance.
h. The Cybex Norm (Figure 35) was used to measure isokinetic power and
endurance in shoulder internal and external rotation, shoulder flexion and
extension as well as elbow flexion and extension.
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Figure 35: The Cybex Norm.
3.2 PROCEDURES
3.2.1 The questionnaire:
Before the physical tests could start, the subjects had to complete a
questionnaire documenting their tennis history as well as their medical history.
The information retrieved from the questionnaire was used to divide the subjects
into a control group and an experimental group. At the end of the questionnaire a
detailed explanation followed that clearly outlined the purpose of the research,
what was to happen with the results obtained from the study, and also what was
expected of the subjects. At the end of the questionnaire they had to sign a
declaration that they agreed to take part in the research according to the set
conditions (See Appendix A).
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3.2.2 Sub-dividing of subjects into groups:
The subjects were divided into a control group and an experimental group as
described in 3.1.1.
3.2.3 Physical Testing procedures:
The tests commenced with a postural and body composition analysis, followed
by other scientific tests.
3.2.3.1
Postural Analysis:
The screening procedure that was used to examine the back included
various observations. Firstly, the athlete stood in an erect position,
and thereafter in the forward bending position. In the standing
position observations were made for asymmetries of the lateral
contours of the trunk, the shoulders, scapula, and lateral deviations of
the spinal process (Becker, 1986).
Figure 36: Postural analysis: The athlete standing in an erect position in order to
determine asymmetries of the neck, shoulders, back and hips.
Schober’s test (Becker, 1986; Smith, 2003) was used to identify normal thoracic
spine motion. According to Schober’s test, spine motion is normal when a mark
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10 cm above the sacral dimples increased with 5 cm in full flexion. This is the
procedure used in the test to identify scoliosis. A pen was used to mark the
sacral dimples and a mark was made 10 cm above the dimples. With the subject
in full flexion of the back, the distance between the two marks was taken again. If
the distance did not increase by 5 cm, it was an indication that scoliosis was
present (Becker, 1986).
Figure 37: Shrober’s test were used to determine thoracic spine motion.
(a) Marking the sacral dimples. (b) Measuring the distance between the sacral
dimples and the 10cm mark in a bending position.
3.2.3.2
Body Composition:
a. Height measurement:
The Harpenden anthropometer was used to measure normal standing height.
The subject stood barefoot in a normal standing position with the feet together
and the back straight against the wall, as seen in figure 38.
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Figure 38: Height measurement using the Harpenden Antropometer.
b.
Body mass measurement:
The Detecto Standing scale was used to measure total body weight
to the nearest 0.1 kilogram with the subject standing barefoot on
the scale as seen in figure 39.
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Figure 39: Body weight measurement using the Detecto Standing Scale.
c.
Fat Percentage:
The fat percentage of the subject was measured by using the Drinkwater Ross
method for testing athletes. This measurement consists of 7 skinfolds, 9
circumferences and 6 sites of breadths.
Specifications for obtaining fat percentage:
Marking Midacromial-Radiale: Arm girth, triceps, and biceps: A line was
marked horizontally to the long axis of the humerus at the mid-acromialeradiale distance, which was determined by an anthropometric tape. The
horizontal line was then extended to the posterior surface of the arm. A
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vertical line at the most posterior surface was then made to intersect with the
horizontal line to mark the site where the triceps skinfold was raised. The
biceps were marked by following the same procedure on the anterior side of
the arm (MacDougall et al., 1991).
•
Skinfolds:
The right hand side is used for the purpose of the description of the
measuring sites. In the actual test, the dominant side of the subjects was
used.
Figure 40: Measuring the skinfold of the Triceps muscle with the Skinfold
Caliper.
Î Biceps: The caliper was applied 1 cm distally from the left thumb and the
index finger and a vertical fold was raised at the marked mid-acromial-radiale
line on the anterior surface of the right arm (MacDougall et al., 1991).
Î Triceps: The caliper was applied 1 cm distally from the index finger and
the left thumb, raising a vertical fold at the marked mid-acromiale-radiale line
on the posterior surface of the arm (Roy & Irvin, 1983; MacDougall et al.,
1991).
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Î Subscapula: The caliper was applied 1cm distally from the left thumb and
index finger, raising a fold oblique to the inferior angle of the scapula in a
direction running obliquely downwards and laterally at an angle of about 45º
from the horizontal (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Supra iliac: The caliper was applied 1cm anteriorly from the left thumb
and the index finger, raising a fold immediately superior to the iliac crest at
the midaxillary line. This folds goes anteriorly downward and usually becomes
progressively smaller as you move away from this point (Roy & Irvin, 1983;
MacDougall et al., 1991).
Î Para umbilicus: The caliper was applied 1cm inferiorly to the left thumb
and index finger. A fold was raised 5cm laterally to the omphalion (midpoint of
the navel) (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Medial thigh: The caliper was applied 1cm distally to the left thumb and
index finger, raising a fold anteriorly on the right thigh along the long axis of
the femur with the leg flexed at a 90º angle at the knee by placing the foot on
a box. The measuring site is estimated at half-distance between the inguinal
crease and the anterior patellae (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Calf: The caliper was applied 1cm distally to the left thumb and index
finger, raising a vertical fold on the relaxed medial aspect of the right calf at
the estimated greatest circumference. The subject’s knee was flexed at 90º
and the foot placed on a box (Roy & Irvin, 1983; MacDougall et al., 1991).
•
Girths:
Î Biceps relaxed: This measurement was taken at the marked midacromiale-radiale distance with the subject standing in an erect position with
the relaxed arm hanging at the side (MacDougall et al., 1991).
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Î Biceps flexed and tense: This measurement was taken at the maximum
circumference of the dominant arm. The arm was raised to the horizontal
position in the sagittal plane with a fully supinated forearm flexed at the elbow
to approximately 45º. The subject made a muscle by fully tensing the biceps
while the tape was adjusted to the maximal girth where the reading was taken
(Roy & Irvin, 1983; MacDougall et al., 1991).
Î Fore arm girth: This was the maximal girth measurement taken from the
dominant forearm with the hand held palm up and relaxed. This measurement
was made no more than 6cm distal from the radiale (MacDougall et al., 1991).
Î Wrist girth: This is the perimeter that was taken of the right wrist distal to
the styloid processes (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Chest girth: The perimeter was taken at the mesosternale. The subject
abducted the arms slightly while the measuring tape was placed to the
horizontal level of the marked mesosternale. The reading was obtained at the
end of a normal expiration (end tidal) (MacDougall et al., 1991).
Î Waist girth: The perimeter was taken at the noticeable waist narrowing
and was located approximately halfway between the costal border and the iliac
crest (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Hip girth (Gluteal): This perimeter was taken at the greatest posterior
protuberance, approximately at the level of the symphysion pubis. The subject
stood in an erect position with the gluteal muscles relaxed (Roy & Irvin, 1983).
Î Thigh girth: This perimeter was taken of the dominant thigh with the
subject standing erect with the feet shoulder- width apart and the weight
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evenly distributed on both feet. The tape was raised to a level 1 to 2 cm below
the gluteal line (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Calf girth: This perimeter was taken of the dominant thigh with the subject
standing erect with the feet shoulder- width apart and the weight evenly
distributed on both feet. Moving the tape and making a series of girth
measurements to ensure the largest value obtained this measurement (Roy &
Irvin, 1983; MacDougall et al., 1991).
Î Ankle girth: This perimeter was taken at the narrowest part of the lower
leg superior to the sphyrion tibiale. Loosening and tightening in order to obtain
the minimal girth measurement manipulated the tape (Roy & Irvin, 1983).
•
Obtaining Breadths:
Figure 41: Measuring the width of the humerus using a Wide-Spreading
Caliper.
Î Biacromial breadth: This is the distance taken between the most lateral
points on the acromion processes with the subject standing erect with the
arms hanging relaxed at the sides. The branches of the caliper pointed
upwards at an angle of about 45º from the horizontal to encompass the largest
diameter between the acromial processes (MacDougall et al., 1991).
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Î Transverse chest width: This is the distance taken of the lateral aspect of
the thorax at the level of the most lateral aspect of the fourth rib. The
measurement was taken from the front with the subject sitting erect. The
caliper was applied at an angle of about 30º downward from the horizontal in
order to avoid the pectoral and the lattisimus dorsi muscles contours. The
measurement was taken at the end of the normal expiratory excursion (end
tidal) (Roy & Irvin, 1983; MacDougall et al., 1991).
Î Iliocristal breadth: This is the distance taken between the most lateral
points on the superior border of the iliac crest. The branches of the caliper
pointed upward at a 45º angle from the horizontal to encompass the largest
diameter between the lateral aspects of the iliac crest (Roy & Irvin, 1983).
Î Anterior/posterior chest depth: This is the depth of the test that was
measured at mesosternale level. The measurement was obtained with the
subject sitting erect. The caliper was applied over the right shoulder in a
downward direction. The one end of the caliper was placed on the
mesosternale and the other point on the spinous process of the vertebra at the
level of the mesosternale (Roy & Irvin, 1983; MacDougall et al., 1991).
ÎHumerus width: This is the distance taken between the medial and lateral
epicondyles of the humerus. The arm was raised forward to the horizontal and
the forearm flexed 90º at the elbow (MacDougall et al., 1991).
Î Femur width: This is the distance taken between the medial and lateral
epicondyles of the femur. The subject was in a sitting position with the leg
flexed at the knee to form a right angle with the thigh (Roy & Irvin, 1983).
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3.2.3.3
Flexibility:
Flexibility tests were used to measure the range of motion of the
shoulder. The following flexibility tests were done:
i) Shoulder internal and external rotation:
(a)
(b)
(c)
Figure 42: Measuring flexibility of the shoulder rotators: (a) neutral
position, (b) external rotation, and (c) internal rotation.
Î Starting position: The subject lied in a supine position on the bed with
the arm bent 90º with the elbow in line with the shoulder. The arm stayed
90º bend throughout the process.
Î Movement: The hand and forearm first moved downward and forward in
an arc as far as possible and the reading were taken for internal rotation.
The hand and forearm were then moved back and upwards in an arc as far
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as possible. The reading was then taken for external rotation. The radial
ulnar joint stayed supinated throughout the measurements.
ii) Shoulder flexion and extension:
(a)
(b)
(c)
Figure 43: Measuring flexibility of the shoulder flexors and extenders.
(a) Neutral position. (b) Shoulder extension. (c) Shoulder flexion.
Î Starting position: The subject stood at a projecting corner of a wall, with
the arm to be measured extending just beyond the projecting corner. The
back stayed flat against the wall with the shoulder blades, buttocks and the
heels touching the wall.
Î Movement: The arm was first moved forward and upwards in an arc as far
as possible and the reading were taken for shoulder flexion. Thereafter the
arm moved downwards and backwards in an arc as far as possible and
reading was taken for shoulder extension. The elbow stayed in an extended
position throughout the measurements.
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3.2.3.4
Functional strength:
Functional shoulder muscle strength and endurance were determined by
measuring:
Î Maximum push-ups in 1 minute: All subjects were to hold the proper
push-up position. The hands were just more than shoulder width apart with
the fingers pointing forwards. The whole body went down as one unit with
the hips staying in line with the feet and shoulders. The chest had to stop
10cm above the floor.
Figure 44: Demonstrating the correct push-up position.
3.2.3.5
Isokinetic strength:
The Cybex Norm was used to measure muscle strength and endurance in
the shoulder girdle. The following movements were recorded:
Î Shoulder flexion & extension:
60º:
3 Warm-ups at 50%, 75% and 100% respectively;
5 maximal efforts recorded.
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180º:
3 Warm-ups at 50%, 75% and 100% respectively;
20 maximal efforts recorded
Figure 45: Isokinetic muscles strength of shoulder flexion and extension
measured on the Cybex Norm.
Î Shoulder abduction & adduction:
60º:
3 Warm-ups at 50%, 75% and 100% respectively;
5 maximal efforts recorded.
180º:
3 Warm-ups at 50%, 75% and 100% respectively;
20 maximal efforts recorded
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(a)
(b)
Figure 46: Isokinetic muscles strength of the (a) shoulder adductors and
(b) shoulder abductors measured on the Cybex Norm.
Î Shoulder internal & external rotation:
60º:
3 Warm-ups at 50%, 75% and 100% respectively;
5 maximal efforts recorded.
180º:
3 Warm-ups at 50%, 75% and 100% respectively;
20 maximal efforts recorded
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(a)
(b)
Figure 47: Isokinetic muscle strength of the shoulder. (a) Internal rotators.
(b) External rotation, measured on the Cybex Norm.
As an indication of the correct muscle balance in the shoulder, the external
rotator muscles have to produce approximately 60% to 80% of the torque
values that is generated by the internal rotators (Perrin, 1993).
Table 15: Normative Values of the Shoulder Internal and External Rotation
Peak Torque (ft-lb.) (Perrin, 1993).
Gender
Speed
Dominan
Non-
Dominant
Non-
Dominant
Non-
º/sec
t
dominant
External rotation
dominant
external /
dominant
Internal
external
internal
external /
rotation
rotation
rotation
internal
ratio
rotation
Internal
rotation
ratio
M
60
42.0
39.0
26.0
24.0
.63
.62
F
60
17.0
17.0
12.0
11.0
.70
.71
M
180
32.7
.70
.81
21.1
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F
180
17.1
11.2
17
.80
Table 16: Normative Values of the Shoulder Flexion and Extension Peak
Torque (ft-lb.) (Perrin, 1993).
Gender
Speed
Dominan
Non-
Dominant
Non-
Dominant
Non-
º/sec
t
dominant
Extension
dominant
Flexion /
dominant
Extension
Extensio
Flexion /
n ratio
Extensio
Flexion
Flexion
n ratio
M
60
57.0
39.0
F
60
28.0
18.0
.77
.81
M
180
49.0
30.0
.74
.81
F
180
19.0
11.0
.84
.82
Table 17: Normative Values of the Shoulder Abduction and Adduction Peak
Torque (ft-lb.) (Perrin, 1993).
Gender
Speed
Dominan
Non-
Dominant
Non-
Dominant
Non-
º/sec
t
dominant
Abduction
dominant
Abductio
dominant
Adduction
n/
Abductio
adductio
n/
n ratio
Adductio
Abduction
Adduction
n ratio
M
60
39.0
37.0
63.
60.0
.66
.65
F
60
19.0
19.0
32.0
30.0
.61
.66
M
180
35.2
32.6
55.9
47.6
.49
.56
F
180
22.5
22.0
39.0
38
.74
.82
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3.3 RESEARCH DESIGN
The type of research done in this study, was “theory testing” research (Mouton &
Marais, 1992) where the data of the research was based on existing theories and
models. The aim of the researcher is to test the effect of scientific exercise
programmes in the sport world.
The researcher needed proof that by following specific scientific exercises it will
prepare the tennis player for the stresses of the game and in this way reduce the
occurrence of shoulder injuries throughout the year. Following basic existing
models and concepts of tennis strengthening helped to achieve this.
The specific tests that were applied included:
•
Posture analysis;
•
Body composition;
•
Flexibility;
•
Functional strength of the upper body; and
•
Isokinetic power and endurance of the shoulder muscles.
According to Mouton & Marais (1992) the following two aspects are necessary in
order to achieve internal validity:
a. The connections of the central concepts have to be very clear,
unambiguous and articulated; and
b. The denotations of the central concepts in the problem setting have to be
accurate indicators of the connections that are used.
The aim and purpose of this kind of design for a research study was to determine
the effect of a specifically designed Biokinetic programme on the prevention and
rehabilitation of shoulder injuries in junior tennis players. The question had to be
answered, whether there is a difference between the occurrence of shoulder
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injuries in tennis players who follow a specific shoulder exercise programme and
those players who just do the normal gymnasium exercise programmes.
3.4
STATISTICAL ANALYSIS
In research it is very important that the number of subjects, their characteristics
as well as their representative nature of the sample are taken into consideration.
In this universal study done, a group of subjects was measured and the results
are representative of elite tennis players (Mouton & Marais, 1992).
The data analysis had the following aims:
•
to determine whether significant differences existed between the 2 groups
on all variables measured;
•
to determine whether significant differences existed between the T1 and
T3 measurements within the same group; and
•
to determine whether there were significant changes in the measurements
taken at different time intervals within the same group.
Since the sample was relatively small and consisted of only 22 and 20
respondents per group respectively, use was made of non-parametric statistics to
analyze the data. Non-parametric tests, also known as distribution-free tests, are
a class of tests that does not rely on a parameter estimation and/or distribution
assumptions (Howell, 1992). The major advantage attributed to these tests is that
they do not rely on any seriously restrictive assumptions concerning the shape of
the sampled populations and thus accommodates small samples as in the case
of this study.
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3.4.1 The following statistical data analysis procedures were used:
a. Descriptive statistics:
Descriptive statistics are primarily aimed at describing the data. The mean,
standard deviation, minimum and maximum scores for each measurement per
group were determined for reference purposes (Howel, 1992).
b. Inferential statistics:
Inferential statistics test the hypotheses about differences in populations on the
basis of measurements made on samples of subjects (Tabachnick & Fidell,
1996).
c. The Mann-Whitney Test:
The Mann-Whitney test is used for testing differences between means when
there are two conditions and different subjects have been used in each condition.
This test is a distribution-free alternative to the independent samples t-test. Like
the t-test, Mann-Whitney tests the null hypothesis that two independent samples
(groups) come from the same population (not just populations with the same
mean). Rather than being based on parameters of a normal distribution like
mean and variance, Mann-Whitney statistics are based on ranks. The MannWhitney statistic is obtained by counting the number of times an observation from
the group with the smaller sample size precedes an observation from the larger
group. It is especially sensitive to population differences in central tendency
(Howell, 1992). The rejection of the null hypothesis is generally interpreted to
mean that the two distributions had different central tendencies. This test was
used to determine significant differences between the experimental group and
the control group on all variables measured.
d. The Wilcoxon Signed Ranks Test:
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The Wilcoxon Signed Ranks test is used in situations in which there are two sets
of scores to compare, but these scores come from the same subjects. This test is
the distribution-free analogue of the t-test for related samples. According to
Howell (1992) it tests the null hypothesis that two related (matched) samples
were drawn either from identical populations or from symmetric populations with
the same mean. This test was used to determine whether statistically significant
differences existed between the T1 and T3 measurements obtained for various
measures within the same group.
e. Friedman’s rank test for correlated samples:
This test is the distribution free analogue of the one-way repeated measure
analysis of variance. “It is a test on the null hypothesis that the scores of each
treatment were drawn from identical populations, and it is especially sensitive to
population differences in central tendency” (Howell, 1992). This test was used to
determine whether statistically significant differences existed between the
measurements obtained at the different periods within the same group.
In this research, the 95% level of confidence (p < 0,05), as required by Thomas &
Nelson (1990), has been used as the minimum to determine significant
differences among various sets of data.
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CHAPTER 4
RESULTS AND DISCUSSION
The results will be presented in the following ways:
a.
Results of the analysis of the comparison of the two groups on
various measurements.
b.
Results of the analysis of the comparison of the T1 and T3
measurements within the same group across various variables.
This analysis was repeated for both groups.
c.
Results of the analysis of the comparison of the same group across
various variables at different time intervals.
This analysis was
repeated for both groups.
d.
Results of cross-tabulations and frequencies on various variables
for both groups.
4.1 BODY COMPOSITION
4.1.1 Results of the analysis of the comparison of measurements taken at
T1 and T3 of the same group across various variables:
The Wilcoxon Signed Ranks test was used to determine whether statistically
significant changes took place between measurements taken at T1 and at T3,
within the same group regarding the various variables.
The following significant differences in distribution on the 5% level of significance
were found between the results at T1 and T3 in the control and experimental
groups. The results are summarized in Figure 48:
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11.13
11.58
12
10.22
10
Mean Rank
8
6 .00
T1
T3
6
4
2
0
LB M : C ontrol group
M uscle % : E xperim ental group
Figure 48: Statistically significant differences with groups: Body composition (T1
and T3).
The results of Figure 48 indicate the following:
a.
From the distribution of the lean body mass at T3 in the control
group. Thus, the lean body mass at T1 was therefore lower than
the lean body mass at T3 in the control group.
b.
The distribution of the muscle percentage at T1 is significantly
different from the distribution of the muscle percentage at T3 in the
experimental group. Thus, the muscle percentage at T1 was lower
than the muscle percentage at T3 in the experimental group.
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4.1.2 Results of the analysis of the comparison of the same group across
various measurements at different time intervals:
Friedman’s tests were used to determine whether statistically significant changes
took place within the same group across the measurements taken at different
time intervals. The results can be summarized as follows:
Statistically significant differences on the 5% level of significance were found for
the experimental group for fat percentage and muscle percentage at different
time intervals (T1 to T3). A statistically significant difference on the 5% level of
significance was found for the control group for lean body mass at different time
intervals (T1 to T3). The results of the above analysis are presented in Figure 49.
4 .0
3 .5
3 .0
3 .0
2 .4
Mean Rank
2 .5
2 .4
2 .2
2 .2
1 .7
2 .0
1 .5
1 .4
1 .3
1 .5
1 .0
0 .5
0 .0
F a t % E x p e r im e n ta l G r o u p
M u s c le % E x p e r im e n ta l G r o u p
L B M % C o n tr o l G r o u p
Figure 49: Statistically significant differences in Body Composition between T1,
T2 and T3.
T1
T2
T3
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The results of Figure 49 indicate the following:
a.
For the experimental group the fat percentage showed a significant
decrease from T1 to T3;
b.
For the experimental group, the muscle percentage showed a
significant increase from T1 to T3; and
c.
For the control group, the lean body mass showed a significant
increase from T1 to T3.
Discussion: Lean Body Mass and fat percentage:
Researchers such as Roetert & Ellenbecker (1998) and Gokeler et al. (2001)
characterize tennis as a sport in which players must respond to a continuous
series of emergencies. This includes sprinting to the ball, changing direction,
reaching, stretching, lunging, stopping and starting (Muller et al., 2000; Gokeler
et al., 2001). Taking all these characteristics into consideration, players must
address flexibility, strength training and endurance, power, agility and speed,
body composition, aerobic and anaerobic fitness in order to improve their tennis
(Roetert, 2003). The mean heart rate in trained players ranges between 140 and
160 beats per minute, which indicates overall intensity of 60 to 70% of the VO2max (Elliott et al., 1985; Bergeron et al., 1991, Konig et al., 2001). In professional
players, this corresponds to an ergometrically-determined workload within an
aerobic/anaerobic transition range of the treadmill of 13km/h for woman and
14km/h for men at a 1.5º slope (Konig et al., 2001). Apart from the weighttraining programme, both the control and the experimental group still followed
their normal aerobic training programme, therefore the increase in Lean Body
Mass of the control group and the decrease in fat percentage of the experimental
group. According to McArdle et al. (1991) adipose tissue increases either by cell
hypertrophy or fat cell hyperplacia. With a loss in body mass, there is only a
decrease in cell size, but never a decrease in cell number. An increased caloric
output through endurance type exercise provides a significant option of
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144
unbalancing the energy balance equation to bring about weight loss as well as a
desirable modification in body composition (Craig, 1983). The performance of
conventional resistance training programmes combined with caloric restriction,
results in the maintenance of lean body mass compared to a programme that
relies only on diet (McArdle et al., 1991).
Discussion: Muscle percentage:
As mentioned earlier, resistance training has become a very important training
tool in tennis (Kraemer et al., 2003). According to Konig et al. (2001) the
progressive adaptation of top ranked players, induced by years of training and
match play, includes an increase in the muscle mass of the dominant arm.
According to Wilmore (1974), Gollnick (1983), Hakkinen (1988) and McArdle et
al. (1991) this fundamental biological adaptation that takes place in response to
overload training occurs primarily from the enlargement of hypertrophy on the
individual muscle fibres.
4.2 MUSCLE STRENGTH AND ENDURANCE
4.2.1 Results of the analysis of the comparison of the two groups on
various measurements:
The Mann-Whitney U-tests were used to determine whether statistically
significant differences existed between the experimental and control groups on
various variables measured. Since this statistical technique is based on mean
rank, the mean rank scores will be shown in all figures. Statistically significant
differences on the 5% level of significance will be graphically presented.
Statistically significant differences were found at the 5% level of significance
between the control and experimental groups for 1RM bench press at T3 and
maximum number of push-ups in 1 minute at T2 and T3. The results are
summarized in Figure 50.
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25.52
30
25.29
23.31
25
17.84
Mean Rank
20
17.30
14.65
15
Control group
Experimental group
10
5
0
1RM Bench press T3
Push-ups (1 min) T2
Push-ups (1 min) T3
Figure 50: Statistically significant difference between groups: Muscle strength
and endurance.
Results in Figure 50 can be interpreted as follows:
1RM bench press measurements at T3 are lower for the control group than for
the experimental group. This is also true for the maximum number of push-ups in
1 minute at T2 and T3. The control group therefore had lower 1RM bench press
measurements at T3 than the experimental group. The control group also had a
lower maximum number of push-ups in 1 minute at both T2 and T3 than the
experimental group.
4.2.2 Results of the analysis of the comparison of measurements taken at
T1 and T3 of the same group across various variables:
The Wilcoxon Signed Ranks test was used to determine whether statistically
significant changes took place between measurements taken at T1 and at T3,
within the same group regarding the various variables.
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The following significant differences in distribution on the 5% level of significance
were found between the results at T1 and T3 in the control and experimental
groups.
12.83
14
12.72
11.47
12
11.73
10.33
9.50
10
8.64
Mean Rank
8.25
8
6.80
6
4.00
4
T1
T3
4.50
2
0
Grip R:
Experimental
group
Grip L:
Experimental
group
1RM Bench:
Control group
0.00
Grip R: Control
group
Grip L: Control
group
Push-ups (1
min): Control
group
Figure 51: Statistically significant difference within groups: Isokinetic muscle
strength (T1 and T3).
The results of Figure 51 indicate the following:
a. The distribution of the 1RM bench press at T1 is significantly different
from the distribution of the 1RM bench press at T3 in the
experimental group. The 1RM bench press at T1 was therefore
lower than the 1RM bench press at T3 in the experimental group.
University of Pretoria etd – Gouws, K (2006)
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b. The distribution of the grip strength of the dominant hand at T1 is
significantly different from the distribution of the grip strength of the
dominant hand at T3 in the experimental group. Thus, the grip
strength of the dominant hand at T1 was therefore lower than the
grip strength of the dominant hand at T3 in the experimental group.
c. The distribution of the grip strength of the non-dominant hand at T1 is
significantly different from the distribution of the grip strength of the
non-dominant hand at T3 in the experimental group. Thus, the grip
strength of the non-dominant hand at T1 was therefore lower than
the grip strength of the non-dominant hand at T3 in the
experimental group.
d. The distribution of the maximum push-ups in 1 minute at T1 is
significantly different from the distribution of the maximum push-ups
in 1 minute, at T3 in the experimental group. Thus, the maximum
push-ups in 1 minute at T1 were therefore lower than the maximum
push-ups at 1 minute at T3 in the experimental group.
e. The distribution of the grip strength of the dominant hand at T1 is
significantly different from the distribution of the grip strength of the
dominant hand at T3 in the control group. Thus, the grip strength of
the dominant hand at T1 was therefore lower than the grip strength
of the dominant hand at T3 in the control group.
f. The distribution of the grip strength of the non-dominant hand at T1 is
significantly different from the distribution of the grip strength of the
non-dominant hand at T3 in the control group. Thus, the grip
strength of the non-dominant hand at T1 was therefore lower than
the grip strength of the non-dominant hand at T3 in the control
group.
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4.2.3 Results of the analysis of the comparison of the same group across
various measurements at different time intervals:
Friedman tests were used to determine whether statistically significant changes
took place within the same group across the measurements taken at different
time intervals. The results can be summarized as follows:
Statistically significant differences were found on the 5% level of significance for
the experimental group regarding the 1RM bench press, grip strength of the
dominant and non-dominant hands, and maximum push-ups in 1 minute.
A
statistically significant difference, on the 5% level of significance, was found for
the control group for grip strength of the non-dominant hand. The results of the
above analysis are presented in Figures 52 and 53 that follow.
3.5
3.0
2.7
2.6
2.2
Mean Rank
2.5
2.0
2.3
1.8
1.8
1.6
1.6
1.5
1.5
1.0
0.5
0.0
Grip R Experimental group
Grip L Control group
Grip L Experimental group
Figure 52: Statistically significant difference for Muscle Strength and Endurance
between T1, T2 and T3.
T1
T2
T3
University of Pretoria etd – Gouws, K (2006)
149
3 .5
2 .9
2 .8
3 .0
2 .5
Mean Rank
1 .8
1 .8
2 .0
T1
T2
1 .3
1 .3
1 .5
1 .0
0 .5
0 .0
1 R M B e n ch E x p e rim e n ta l G ro u p
P u sh U p s E xp e rim e n ta l g ro u p
Figure 53: Statistical significant differences for Muscle Strength and Endurance
between T1, T2 and T3 (continue).
The results of Figures 52 and 53 indicate the following:
a.
For the experimental group, the 1RM bench press showed a
significant increase from T1 to T3, peaking at T3.
b.
For the experimental group, the grip strength of the dominant as
well as the grip strength of the non-dominant hands showed a
significant increase from T1 to T3.
c.
For the experimental group, the maximum push-ups in 1 minute
showed a significant increase from T1 to T3.
d.
For the control group, the grip strength of the non-dominant hand
showed a significant increase from T1 to T2, from where it showed
a slight increase to T3.
T3
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150
Discussion:
The weight- training programme that was followed by the experimental group, was
based on the principle of “progressive overload”. In order to raise the level of strength
and stamina, the body had to be subjected to an increased resistance through heavier
weights, higher repetitions and longer or more frequent training sessions (Kirkley &
Goodbody, 1986; Kraemer et al., 2003). According to research done by Anderson &
Kearney (1992) and Kraemer et al. (2003) individuals that were exposed to heavier
loads during training experienced greater improvements in maximal strength
performance. Due to the importance of muscular power in tennis, resistance training,
and therefore muscular strength, became a very important training tool to optimize the
neuromuscular performance factors related to the primary strokes in tennis (Kraemer et
al. 2003). The exercise programmes that were followed, were specifically designed to
meet the demands of tennis (Costill & Fox, 1969; Matveyev, 1981; Kirkley & Goodbody,
1986; Kraemer et al., 2003; Roetert, 2003). The inclusion of weights in the training
programme helped to improve explosive speed on the court, muscle strength as well as
muscle endurance (Kirkley & Goodbody, 1986; Roetert, 2003; Salisbury et al., 2003).
4.3. ISOKINETIC MUSCLE STRENGTH
4.3.1 Results of the analysis of the comparison of the two groups on
various measurements:
As indicated previously, Mann-Whitney U-tests were used to determine whether
statistically significant differences existed between the experimental and control
groups on various variables measured.
A statistically significant difference was found on the 5% level of significance
between the control and experimental groups for the strength of the internal
rotators of the non-dominant shoulder at T3. Thus, the control and experimental
groups differed significantly with regard to the strength of the internal rotators of
the non-dominant shoulder at T3. Results can be found in Figure 54 below.
University of Pretoria etd – Gouws, K (2006)
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25 .67
30
17.70
25
C ontrol g ro up
E xperim enta l group
Mean Rank
20
15
10
5
0
C B S hou lder IR non-dom
Figure 54: Statistically significant differences between groups: Isokinetic Muscle
Strength (T3).
From the results in Figure 54 it can be seen that the strength of the internal
rotators of the non-dominant shoulder at T3 was significantly lower for the control
group than for the experimental group.
4.3.2 Results of the analysis of the comparison of measurements taken at
T1 and T3 of the same group across various variables:
The Wilcoxon Signed Ranks test was used to determine whether statistically
significant changes took place between measurements taken at T1 and at T3,
within the same group regarding the various variables.
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152
The following significant differences in distribution on the 5% level of significance
were found between the results at T1 and T3 in the control and experimental
group. The results are summarized in Figures 55 and 56.
12.83
14
12
10.13
9.97
10.69
11.00
10.87
10.41
10.00
10.29
10
Mean Rank
9.40
8
6
6.75
4
2
1.00
0
CB Shoulder IR
dom: Control CB Shoulder
ER non-dom: CB Shoulder IR
group
CB Shoulder IR
dom:
Control group
non-dom:
Experimental
Experimental
group
group
CB Shoulder
ER dom:
Experimental
group
CB Shoulder
ER non-dom:
Experimental
group
Figure 55: Statistically significant differences within groups: Isokinetic Muscle
Strength (T1 and T3).
T1
T3
University of Pretoria etd – Gouws, K (2006)
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12
9.75
11.00
11.33
9.13
8.14
10
7.50
Mean Rank
8
6
T1
T3
4
2
0
CB-SHO Flex non-dom:
Experimental group
CB-Elbow Ext dom:
Experimental group
CB-Elbow Ext non-dom:
Experimental group
Figure 56: Statistically significant differences within groups: Isokinetic Muscle
Strength (continue) (T1 and T3).
The results of Figures 55 and 56 indicate the following:
a. The distribution of the strength of the internal rotators of the
dominant shoulder at T1 is significantly different from the
distribution of the strength of the internal rotators of the dominant
shoulder at T3 in the experimental group. The strength of the
internal rotators of the dominant shoulder at T1 was therefore lower
than the strength of the internal rotators of the dominant shoulder at
T3 in the experimental group.
b. The distribution of the strength of the internal rotators of the nondominant shoulder at T1 is significantly different from the
distribution of the strength of the internal rotators of the nondominant shoulder at T3 in the experimental group. The strength of
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154
the internal rotators of the non-dominant shoulder at T1 was
therefore lower than the strength of the internal rotators of the nondominant shoulder at T3 in the experimental group.
c. The distribution of the strength of the external rotators of the
dominant shoulder at T1 is significantly different from the
distribution of the strength of the external rotators of the dominant
shoulder at T3 in the experimental group. The strength of the
external rotators of the dominant shoulder at T1 was therefore
lower than the strength of the external rotators of the dominant
shoulder at T3 in the experimental group.
d. The distribution of the strength of the external rotators of the nondominant shoulder at T1 is significantly different from the
distribution of the strength of the external rotators of the nondominant shoulder at T3 in the experimental group. The strength of
the external rotators of the non-dominant shoulder at T1 was
therefore lower than the strength of the external rotators of the nondominant shoulder at T3 in the experimental group.
e. The distribution of the strength of the flexor muscles for the nondominant shoulder at T1 is significantly different from the
distribution of the strength of the flexor muscles for the nondominant shoulder at T3 in the experimental group. The strength of
the flexor muscles for the non-dominant shoulder at T1 was
therefore lower than the strength of the flexor muscles for nondominant shoulder at T3 in the experimental group.
f. The distribution of the strength of the elbow extensors for the
dominant elbow at T1 is significantly different from the distribution
of the strength of the elbow extensors for the dominant elbow at T3
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155
in the experimental group. The strength of the elbow extensors for
the dominant elbow at T1 was therefore lower than the strength of
the elbow extensors for dominant elbow at T3 in the experimental
group.
g. The distribution of the strength of the elbow extensors for the nondominant elbow at T1 is significantly different from the distribution
of the strength of the elbow extensors for the non-dominant elbow
at T3 in the experimental group. The strength of the elbow
extensors for the non-dominant elbow at T1 was therefore lower
than the strength of the elbow extensors for non-dominant elbow at
T3 in the experimental group.
h. The distribution of the internal rotators of the non-dominant
shoulders at T1 is significantly different from the distribution of the
internal rotators of the non-dominant shoulders at T3 in the
experimental group. The internal rotators of the non-dominant
shoulders at T1 were therefore lower than the internal rotators of
the non-dominant shoulders at T3 in the experimental group.
i. The distribution of the external rotators of the dominant shoulders
at T1 is significantly different from the distribution of the external
rotators of the dominant shoulders at T3 in the experimental group.
The external rotators of the dominant shoulders at T1 were
therefore lower than the external rotators of the dominant shoulders
at T3 in the experimental group.
j.
The distribution of the external rotators of the non-dominant
shoulders at T1 is significantly different from the distribution of the
external rotators of the non-dominant shoulders at T3 in the
experimental group. The external rotators of the non-dominant
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156
shoulders at T1 were therefore lower than the external rotators of
the non-dominant shoulders at T3 in the experimental group.
Discussion:
According to Costill & Fox (1969), Matveyev (1981), Kirkley & Goodbody (1986),
Kraemer et al. (2003) and Roetert (2003) the importance of specificity of training
cannot be stressed enough. One thing that strongly emerges, is the fact that
training has to be geared to the specific sport that the athlete is training for
(Fleck, 1999; Kraemer et al., 2003). Most injuries in tennis are typical overuse
injuries (Priest & Nagel, 1976; Schmidt-Wiethoff et al., 2000; Roetert, 2003),
resulting from repetitive stresses and minor traumatic events, as well as muscle
imbalances (Reece et al., 1986; Roetert & Ellenbecker, 1998; Meister, 2000).
Typically in tennis, the anterior muscles of the shoulder and the chest (pectoralis
and anterior deltoids) are stronger than the rotator cuff and the upper back
muscles that support the scapula (Roetert & Ellenbecker, 1998). The programme
of the experimental group focused on strengthening of the rotator cuff muscles
on the dominant and non-dominant side as well as the internal rotators of the
non-dominant arm that plays a key role in the double-handed backhand. Other
muscles used in the double-handed backhand include the latissimus dorsi,
clavicular pectoralis, sternocostal pectoralis and the anterior deltoid (Hay & Reid,
1999; Gokeler et al., 2001; Martini et al. 2001; Schmidt-Wiethoff et al., 2003).
University of Pretoria etd – Gouws, K (2006)
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4.4 FLEXIBILITY
4.4.1 Results of the analysis of the comparison of measurements taken at
T1 and T3 of the same group across various variables:
The Wilcoxon Signed Ranks test was used to determine whether statistically
significant changes took place between measurements taken at T1 and at T3,
within the same group regarding the various variables.
The following significant differences in distribution on the 5% level of significance
were found between the results at T1 and T3 in the control and experimental
groups. The results are summarized in Figure 57 that follows.
14
11.68
11.73
12
9.42
10.06
9.94
Mean Rank
10
7.75
8
6.80
5.75
6
T1
T3
5.00
4
2
2.00
0
Shoulder ER nondom: Control group Shoulder IR dom:
Experimental group
Shoulder IR nondom: Experimental
group
Shoulder ER dom:
Experimental group
Shoulder ER nondom: Experimental
group
Figure 57: Statistically significant differences within groups: Flexibility (T1 and
T3).
University of Pretoria etd – Gouws, K (2006)
158
The results of Figure 57 indicate the following:
a. The distribution of the internal rotators of the dominant shoulders at
T1 is significantly different from the distribution of the internal
rotators of the dominant shoulders at T3 in the experimental group.
The internal rotators of the dominant shoulder at T1 were therefore
lower than the internal rotators of the dominant shoulder at T3 in
the experimental group.
b. The distribution of the internal rotators of the non-dominant
shoulders at T1 is significantly different from the distribution of the
Internal rotators of the non-dominant shoulders at T3 in the
experimental group. The internal rotators of the non-dominant
shoulder at T1 were therefore lower than the internal rotators of the
non-dominant shoulder at T3 in the experimental group.
c. The distribution of the external rotators of the dominant shoulders
at T1 is significantly different from the distribution of the external
rotators of the dominant shoulders at T3 in the experimental group.
The external rotators of the dominant shoulder at T1 were therefore
lower than the external rotators of the dominant shoulder at T3 in
the experimental group.
d. The distribution of the external rotators of the non-dominant
shoulders at T1 is significantly different from the distribution of the
external rotators of the non-dominant shoulders at T3 in the
experimental group. The external rotators of the non-dominant
shoulder at T1 were therefore lower than the external rotators of the
non-dominant shoulder at T3 in the experimental group.
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159
e. The distribution of the external rotators of the non-dominant
shoulders at T1 is significantly different from the distribution of the
external rotators of the non-dominant shoulders at T3 in the control
group. The external rotators of the non-dominant shoulder at T1
were therefore lower than the external rotators of the non-dominant
shoulder at T3 in the control group.
Discussion:
According to the results, the experimental group showed an improvement in the
flexibility of the internal and external rotators in both the dominant and the nondominant shoulders, where the control group only improved on the external
rotators of the non-dominant shoulder. According to Roetert & Ellenbecker (1998)
an important factor contributing to overuse injuries in the shoulder is muscle
imbalance (Muller et al., 2000). It is therefore important that the exercise
programme allows for the improvement of muscle imbalances both in strength
and flexibility (Kirshblum et al., 1997, Gokeler et al., 2001). Most tennis players
are flexible in the external shoulder rotation due to the serving action, but have
limited internal rotation on their tennis playing side (Roy et al., 1995; Kirshblum et
al., 1997). Specific flexibility exercises help to overcome imbalances created by
tennis and other daily activities and they lighten the intensity of work of the
opposing muscle groups by providing less restricted motion (Roy et al., 1995;
Roetert & Ellenbecker, 1998). Flexibility can be defined as the degree in which
the muscles, tendons and connective tissues around the joints can elongate and
bend (Burnham et al., 1993; Roy et al., 1995; Kirshblum et al., 1997, Salisbury et
al., 2003). In tennis a player is required to make shots that places his body parts
in extreme ranges of motion. If the player can maintain strength throughout a
flexible, unrestricted range of motion it will help prevent injuries and enhance
performance (Roy et al., 1995; Salisbury et al., 2003). Static flexibility was used
as an indication of the amount of motion that the player has around a joint or
series of joints while at rest (Kirshblum et al., 1997; Burnham et al., 1993;
Kirshblum et al., 1997; Salisbury et al., 2003). Dynamic flexibility is very
University of Pretoria etd – Gouws, K (2006)
160
important in tennis, for it describes the active range of motion about the joints
and represents the amount of movement the player has available for executing
serves, groundstrokes and volleys (Roy et al., 1995; Roetert & Ellenbecker,
1998; Salisbury et al., 2003). The joint structure’s resistance to motion limits
dynamic flexibility, as well as the ability of the soft tissue (muscles and tendons)
to deform and the neuromuscular components of the body, including the nerves
(Roy et al., 1995; Salisbury et al., 2003). Heat increases the elongation and
bending properties of soft tissue in the body. Warming up before stretching raises
the body’s core temperature and provides greater gains in flexibility with less
micro trauma to the tissues being stretched (Roetert & Ellenbecker, 1998;
Salisbury et al., 2003). Also when a muscle is stretched quickly, the muscle
spindle sends a message to the central nervous system to contract the muscle
(Burnham et al., 1993; Schmidt-Wiethoff et al., 2000). This stretch reflex causes
the muscle to shorten and contract, therefore hindering the stretching process
(Burnham et al., 1993; Roetert & Ellenbecker, 1998).
4.5 POSTURE MEASURES
4.5.1 Scoliosis
Use was made of frequency tables to determine the percentage of players with
scoliosis within each group (experimental and control) for T1 compared to T3. A
player is said to have scoliosis when his posture is either convex to the dominant
side or convex to the non-dominant side.
Use was also made of the same
frequency tables to determine the percentage of players within each group that
are convex to the dominant side and convex to the non-dominant side for T1
compared to T3. Results for this analysis can be found in Tables 18 and 19 that
follow.
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Table 18: Frequency tables for Scoliosis for the control and experimental groups
for T1.
Group
Control
Group
Valid
Experimental
Group
Valid
Cv
Level
Total
cv
cv
nor
Total
Frequency
Percent
9
13
22
5
1
14
20
40.
59.
100.
25.
5.0
70.
100.
Valid %
40.
59.
100.
25.
5.0
70.
100.
Cumulative
%
40.
100.
25.
30.
100.
Table 19: Frequency tables for Scoliosis for the control and experimental groups
for T3.
Grou
Control
Group
Valid
Cv
Cv
Leve
Total
Experimental
Group
Valid
Cv
Cv
cv
nor
No
Total
Frequency Percent
11
50.
1
4.5
10
45.
22
100.
5
25.
1
5.0
5
25.
4
20.
5
25.
20
100.
Valid
Percent50.
4.5
45.
100.
25.
5.0
25.
20.
25.
100.
Cumulative
%50.
54.
100.
50.
55.
25.
75.
100.
0
From results in Tables 18 and 19 the following can be seen:
a. For the control group, 54.5% of players had scoliosis at T1, compared to
55% of the experimental group.
b. For the control group at T3, 40.9% of players had scoliosis compared to
the 30% in the experimental group.
c. Although the percentage of players with scoliosis in both the control and
experimental groups showed a decrease from T1 to T3, the players in the
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experimental group showed a larger decrease than those in the control
group.
d. Fifty percent (50%) of players in the control group were convex to the nondominant side at T1, compared to the 4.5% that was convex to the
dominant side. At T3, 40.9% of players in the control group were convex
to the non-dominant side with none of the players being convex to the
dominant side.
e. The players in the experimental group showed a similar trend than those
in the control group at T1.
Fifty percent (50%) of players in the
experimental group were convex to the non-dominant side compared to
the 5% that was convex to the dominant side. At T3, 25% of players in the
control group were convex to the non-dominant side with 5% still being
convex to the dominant side.
4.5.2 Shoulder height
Use was made of frequency tables to determine the shoulder height of players in
both the control and experimental groups at T1 and T3.
A summary of the
analysis can be found in Tables 20 and 21 that follow:
Table 20: Frequency tables for the control and experimental groups for shoulder
height at T1.
Group
Control
Group
Valid
Experimental
Group
Valid
ND
Leve
Total
ND
level
D
Total
Frequency
Percent
14
8
22
10
9
1
20
63.
36.
100.
50.
45.
5.0
100.
Valid
Percent
63.
36.
100.
50.
45.
5.0
100.
Cumulative
Percent
63.
100.
50.
95.
100.
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Table 21: Frequency tables for the control and experimental groups for shoulder
height at T3.
Group
Frequency
Control
Group
Experimental
Group
Valid
ND
Leve
Total
Valid
ND
level
D
Total
9
13
22
5
14
1
20
Percent
40.
59.
100.
25.
70.
5.0
100.
Valid
Percent
40.
59.
100.
25.
70.
5.0
100.
Cumulative
Percent
40.
100.
25.
95.
100.
From results in Tables 20 and 21 the following can be seen:
a. For the control group at T1, 63.6% of players’ shoulder heights were not
level. For the experimental group at T1, 55% of the players’ shoulder
heights were not level.
b. At T3, 40.9% of control group players’ shoulder heights were not level,
compared to 30% in the experimental group.
c. At both T1 and T3, the percentage of players with shoulder heights not
level in the control group, was higher than that in the experimental group.
In both the control and experimental groups, the percentage of players
with shoulder heights not level, decreased from T1 to T3.
d. 63.6% of players in the control group’s non-dominant shoulder were
higher than the dominant shoulder at T1, compared to the 40.9% of
players at T3. There were no players in the control group with the
dominant shoulder higher than the non-dominant one.
e. For the players in the experimental group, 50% had a higher nondominant shoulder and 5% a higher dominant shoulder at T1, compared to
25% and 5% respectively, at T3. Those with the non-dominant shoulder
being higher at T1 therefore showed a decrease to T3.
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4.5.3 CM Bend
The CM bend was used to determine whether scoliosis was present. According
to Shrober’s test scoliosis is present when the CM bend is less than 5 cm
(Becker, 1986).
A cross-tabulation was run to determine in what percentage of players, CM bend
was less than 5 in T1 and became greater than 5 in T2. This was done for both
the control and experimental groups. A summary of results can be found in Table
22 below.
Table 22: Cross-tabulation of CM Bend at T1 with CM Bend at T3 for both the
control and experimental groups.
CM Bend
Group
Experimental
Group
CM
B
T1 d
<5
Coun
t% within CM Bend
>5
T1
Coun
t% within CM Bend
T1
Coun
t% within CM Bend
Total
Control Group
CM
B d
T1
Total
<5
T1
Coun
>5
% within CM Bend
T1
Coun
% within CM Bend
T1
Coun
t% within CM Bend
T1
<5 T3
8
>5
61.5%
38.5%
5
Total
13
9
100.0
%
9
8
100.0
% 14
100.0
% 22
36.4%
63.6%
100.0
% 10
8
2
80.0%
20.0%
10
100.0
% 10
8
100.0
% 12
100.0
% 20
40.0%
60.0%
100.0
%
From the results in Table 22 the following can be seen:
a. In 38.5% of cases, in the experimental group, CM bend was less than five
in T1 and became more than five in T3.
b. In 20% of cases, in the control group, CM bend was less than five in T1
and became greater than five in T3.
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4.5.4 Higher hip
Use was made of frequency tables to determine the percentage of players within
each group (control and experimental), with hips that were not level. It was also
used to determine the percentage of players with the left hip higher than the right
hip, and the right hip higher than the left hip. This was also done for both groups.
A summary of results can be found in Tables 23 and 24 that follow.
Table 23: Frequency table for the control and experimental groups for Hip Height
at T1.
Group
Frequency
Control
Group
Valid
Experimental
Group
Valid
Leve
D
Total
Leve
D
ND
Total
8
14
22
9
10
1
20
Percent
Valid
36.
63.
100.
45.
50.
5.0
100.
36.
63.
100.
45.
50.
5.0
100.
Cumulative
Percent
36.
100.
50.
100.
5.0
Table 24: Frequency tables for the control and experimental groups for Hip
Height at T3.
Group
Frequency
Control
Group
Valid
Experimental
Group
Valid
Leve
D
Total
Leve
D
ND
Total
13
9
22
14
5
1
20
Percent
Valid
59.
40.
100.
70.
25.
5.0
100.
59.
40.
100.
70.
25.
5.0
100.
Cumulative
Percent
59.
100.
75.
100.
5.0
From the results in Tables 23 and 24 it can be seen that:
a. In the control group at T1, 63.6% of the group’s hips were not level,
compared to 40.9% at T3.
University of Pretoria etd – Gouws, K (2006)
166
b. For the experimental group at T1, 55% of the group’s hips were not level,
compared to 30% at T3.
c. For the control group at T1, 63.6% of players’ dominant hip was higher
than the non-dominant, with none with the non-dominant hip higher than
the dominant. At T3, the percentage with a higher dominant hip decreased
to 40.9%.
d. In the experimental group at T1, 50% of players had a higher dominant hip
and 5% a higher non-dominant hip. At T3, the percentage with the higher
dominant hip decreased to 25% with the percentage with a higher nondominant hip staying stable at 5%.
Due to the small sample size, any relationship that might exist between scoliosis
and hip height could not be determined by using cross-tabulation with Chi-square
analysis.
4.5.5 Kyphosis
Frequency tables were used to determine the percentage of players with
kyphosis in both the control and experimental groups at T1 and T3. Results are
summarized in Figure 58 below.
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75.00
63.64
55.00
65.00
46.00
55.00
Percentage (%)
45.00
30.00
35.00
25.00
15.00
5.00
-5.00
Control Group
Experimental Group
Figure 58: Percentage of players within each group with kyphosis at T1 and T3.
From the results in Figure 58 it can be seen that the percentage of players with
kyphosis in both the control and experimental groups decreased from T1 to T3:
a. In the control group, the percentage of players with kyphosis decreased
from 63.64% at T1 to 46% at T3.
b. In the experimental group, the percentage of players with kyphosis
decreased from 55% at T1 to 30% at T3.
c. The percentage of players with kyphosis was higher for the control group
than for the experimental group at both T1 and T3.
T1
T3
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4.5.6 Lordosis
Frequency tables were used to determine the percentage of players with lordosis
in both the control and experimental groups at T1 and T3.
Results are
summarized in Figure 59 below.
60.0
50.0
50.0
40.9
Percentage
40.0
30.0
25.0
30.0
20.0
10.0
0.0
Control Group
Experimental Group
Figure 59: Percentage of players with Lordosis in both groups at T1 and T3.
From Figure 59, it can be seen that the percentage of players with lordosis in
both the control and experimental groups decreased from T1 to T3:
a. In the control group, the percentage of players with lordosis decreased
from 50.0% at T1 to 40.7% at T3.
b. In the experimental group, the percentage of players with lordosis
decreased from 30% at T1 to 25% at T3.
The percentage of players with lordosis was higher for the control group than for
the experimental group at both T1 and T3.
T1
T3
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169
Discussion:
As mentioned by Skrez (2003) children are involved in competitive sport from an
early childhood. The various types of stresses to which they are exposed can
effect the growth and the development of their maturing musculoskeletal systems
and it could disrupt the normal growth pattern (Skrez, 2003; Walker, 2003). The
most serious of all the growth disorders is scoliosis, due to the fact that the body
may disform and then inhibit normal bodily organ function (Becker, 1986; Walker,
2003). Katz (2003) and Milan (2003) found that side - bending exercises, as well
as trunk rotation exercises could improve the condition of scoliosis. The exercise
programme also focused on strengthening of the back in order to perform up to
the demands of tennis. This produced an increase in all the normal curves of the
spine (Hauser, 1937; Carlson, 2003; Skrzek, 2003). Another aspect taken care of
in the programme, is “poor posture”, which is the result of imbalances between
the anterior and posterior structures of the back (Katz, 2003). A strong back can
withstand the demands made on the back, such as overload (Skrzek, 2003). The
programme further focused on strengthening of the non-dominant side of the
back and stretching of the dominant side in order to restore normal back
curvature. Research done by Becker (1986) and Skrzek (2003) showed that the
curvature is usually convex to the dominant arm, due to muscle imbalances
(Becker, 1986; Skrzek, 2003).
4.6 GRADES OF INJURIES
Injuries were graded as follows:
a. Grade 1: Old injury – shoulder pain but player kept on playing.
b. Grade 2: New injury – shoulder pain but player kept on playing.
c. Grade 3: Old injury – shoulder injury where player has to stop playing.
d. Grade 4: New injury – shoulder injury where player has to stop playing
e. Grade 5:
operation.
Old injury – serious shoulder injury where player needs an
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170
f. Grade 6: New injury – serious shoulder injury where player needs an
operation.
Frequency tables were used to determine how many injuries (per grade of injury)
occurred at each measurement (T1, T2 and T3). A summary of results can be
found in Figures 60 and 61 that follow.
100
90
85
85
80
Percentage (%)
70
60
55 55
50
T1
T2
T3
40
30
30
20
15
15
10 10
10
10
5
5
5
0
0
0
Gr1
Gr2
Gr3
0
0
Gr4
Grade of injuries
0
Gr5
0
0
Gr6
Figure 60: Control group: Grades of shoulder injuries (T1, T2 and T3).
None
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80
70
59
60
55 55
Percentage (%)
50
40
T1
T2
T3
30
18
18
20
14
14
14
14
9
9
10
5
5
5
0
0 0
0
Gr1
Gr2
Gr3
5
Gr4
Grade of injuries
Gr5
5
0
Gr6
0
None
Figure 61: Experimental group: Grades of shoulder injuries (T1,T2 and T3).
The results in Figures 60 and 61 show the following:
a.
No injuries:
In the control group:
-
the players with no injuries stayed stable from T1 (54.5%) to T2
(54.5%) where after it increased to 59.1% at T3;
In the experimental group:
-
the players with no injuries stayed stable from T1 (55.0%) to T2
(55.0%) where after it increased to 85% at T3.
Discussion:
Both the control and the experimental group showed a decrease in injuries
towards T3, with the experimental group showing a much greater improvement
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with fewer injuries occurring. According to Reece et al. (1986), Kibler et al.
(1988), Lehman (1988), Schmidt-Wiethoff et al., (2000); and Roetert (2003), 80%
of all tennis injuries are caused by overuse. Intensive research done by
Ellenbecker (1995), Roetert & Ellenbecker (1998) and Muller et al. (2000) found
that there are two major factors leading to overuse injuries in the shoulder of
tennis players:
•
weak rotator cuff muscles; and
•
muscle imbalances.
The training programme of the experimental group focused on sport specific
strengthening exercises of the shoulder and rotator cuff muscles. The rotator cuff
exercises that were used are described in Chapter 2.7.1. It was recommended
that the athletes use low-resistance, high-repetition exercises in strengthening
the rotator cuff muscles in order to prevent the body using the larger muscle
groups, such as the trapezius and the deltoid (Roetert & Ellenbecker, 1998;
Schmidt-Wiethoff et al., 2000; Roetert, 2003).
The programme of the experimental group was designed to improve muscle
imbalances (Schmidt-Wiethoff et al., 2000; Schmidt-Wiethoff et al., 2003).
Typically in tennis, the anterior muscles of the shoulder and the chest (pectoralis
and the anterior deltoids) are stronger than the rotator cuff and the upper back
muscles that support the scapula (Roetert & Ellenbecker, 1998). Studies done by
Miyashita et al. (1980), Yoshizawa et al. (1987), Rhu et al. (1988) and
Ellenbecker et al. (2002) show a relative silence of electrical activity in the
acceleration muscles during impact with peak activity occurring just prior to
impact. The infraspinatus, part of the rotator cuff muscles, is the only muscle that
remains active during impact while stabilizing the shoulder. According to the
analysis done of the shoulder muscles in tennis-specific movements in Chapter
2.4, it is clear that a clinically applicable premise regarding the importance of the
rotator cuff and the scapular stabilizers (serratus anterior) can be formulated
(Ellenbecker, 1995; Schmidt-Wiethoff et al., 2000; Roetert, 2003).
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b.
Grade 1 and Grade 2:
In the control group:
-
For both grades 1 and 2 injuries, the percentage of players with
these types of injuries was 13.6% at T1, increased to 18.2% at T2,
and decreased to 13.6% at T3.
In the experimental group:
-
15% of the players had grade 1 injuries at T1. This percentage
increased to 30% at T2 where after it decreased to 15% at T3
again;
-
The percentage of players with Grade 2 injuries remained stable at
10.0% from T1 to T2. None of the players had grade 2 injuries at
T3.
c.
Grade 3:
In the control group:
-
9% of players had grade 3 injuries at T1, with none having them at
T2 and T3.
In the experimental group:
-
The percentage of players with Grade 4 injuries remained stable at
5.0% from T1 to T2. None of the players had grade 3 injuries at T3.
d.
Grade 4:
In the control group:
-
4.5% of players had grade 4 injuries at T1. This stayed more or
less stable at T2 (4.6%) and increased to 9.1% at T3.
In the experimental group:
-
10.0% of players had grade 4 injuries at T1. None of the players
had grade 4 injuries at either T2 or T3.
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Discussion:
The injured players of the experimental group followed a comprehensive
rehabilitation programme that mainly focused on the upper extremity kinetic
chain, served to restore normalized joint arthrokinematics and enabled a full
return to the repetitive musculoskeletal demands of tennis (Ellenbecker, 1995;
Meister, 2000; Ellenbecker et al., 2002). These players also had a thorough
evaluation of the injured shoulder. This evaluation was complete and specific
about the primary diagnosis and the secondary problems that it could cause
(Rubin & Kibler, 2002). According to Kibler & Livingston (2001) the goal of a
functional rehabilitation programme is to restore normal function. The majority of
the rehabilitation exercises were done in the upright position with the feet on the
ground in order to restore normal physiology and proprioseption (Rubin & Kibler,
2002; Schmidt-Wiethoff et al., 2003). After proximal stability was regained,
rehabilitation of the scapula was incorporated, including scapular retraction and
depression. Only after the scapular movements were normal, glenohumeral
rehabilitation proceeded (Rubin & Kibler, 2002). This included restoration of
scapular mobility and rotator cuff activation to restore normal compression. As
soon as the player was able to isolate the rotator cuff muscles, rehabilitation was
further integrated into the context of the kinetic chain by using closed-chain
exercise protocols. In the final phase of rehabilitation plyometric exercises were
incorporated in the exercise programme (Ellenbecker et al., 2002; Rubin & Kibler,
2002; Schmidt-Wiethoff et al., 2003).
e.
Grade 5:
In the control group:
-
4.5% of players had Grade 5 injuries at T1, none had it at T2, and
4.5% had it at T3.
In the experimental group:
-
None of the players had grade 5 injuries at T1, T2 or T3.
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175
f.
Grade 6:
In the control group:
-
Both at T1 and at T3, none of the players had Grade 6 injuries. At
T2, however, 4.6% of players had grade 6 injuries.
In the experimental group:
-
5.0% of players had a grade 6 injury at T1 and none of the players
had this type of injury at T2 or T3.
Discussion:
Effective and thorough post-operative rehabilitation is vital for the successful reentering of the tennis court (Rubin, 2000; Kibler & Livingston, 2001). The
recovery period was divided into four phases:
a. The acute phase included the first three weeks of recovery. The
main objectives were to control the pain, clear soft tissue
restrictions, begin muscle re-education as well as active and activeassisted range of motion exercises (Rubin, 2000; Kibler &
Livingston, 2001).
b. The early recovery phase lasted from week 3 to week 6
postoperatively. The goals were to increase range of movement,
flexibility, strength, control and endurance as well as to restore the
normal kinematics (Rubin, 2000; Sonnery-Cottet et al., 2002).
c. The late recovery phase extended from weeks 6 to 12
postoperatively. The objectives were to restore the full range of
motion and flexibility, further increase strength, power and
endurance through exercises that stress the core-based muscle
synergy,
and
advanced
eccentric
and
concentric
scapular
stabilization (Sullivan, 2001; Rubin & Kibler, 2002).
d. The functional phase began 3 months post-operatively in
conjunction
with
the
coaches’
and
trainers’
sport-specific
progressions. The goals were to restore the sport and work specific
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kinematics, increase strength, power and endurance to a functional
level of play and to restore the required activity specific
coordination, speed and agility (Burkhart & Tehrany, 2002; Rubin &
Kibler, 2002).
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CHAPTER 5
CONCLUSIONS AND RECOMMENDATIONS
Specialization, which is the result of man’s continual striving for improvement and
development, has permeated almost every aspect of today’s modern society
(Ellwanger, 1973; Copley, 1975). According to Copley (1975) sport specialization
generally involves work and scientific research in aspects such as equipment,
training and conditioning, coaching, teaching and administration. Intensive
literature surveys and numerous discussions with leading players and authorities
have indicated that research in tennis compared to other sports has been grossly
neglected with respect to training, conditioning, coaching and teaching of players
(Copley, 1975; Fu & Stone, 1994). Efforts have only recently been made in order
to understand the sport science of tennis. However, since 1990, great strides
have been made in understanding the biomechanics, physiology, psychology,
and sports medicine of tennis. This was done largely through research funded by
the U.S. Tennis Association. Based on this information it is possible to develop
programmes for better identification of injuries, preventative conditioning
programmes and also for better skill acquisition programmes (Fu & Stone, 1994).
At the competitive level, junior players are required to have sound stroke
production and good physical fitness, combined with the psychological
characteristics that enable both successful performance and normal socialization
with children of their own age (Elloitt et al., 1989). The shoulder is of paramount
importance to all competitive tennis players (Plancher et al., 1995). Turner &
Dent (1996) found that 27% of all tennis injuries in junior players occur in the
shoulder region. The shoulder girdle is prone to injuries because of its function to
maximally accelerate and decelerate the arm while it maintains precise control
over the racquet at ball contact (Hagerman & Lehman, 1988; Carson, 1989;
Plancher et al., 1995). The complex interaction between muscle fatigue,
eccentric overload and primary instability with secondary impingement can lead
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to disability in tennis players (Plancher et al. 1995). By exploring and
understanding all the aspects of tennis dynamics, shoulder rehabilitation and
conditioning programmes can be developed that will diminish disability and
enhance performance in tennis players.
A total number of 42 tennis players, training at the Performance Centre and the
International Tennis Federation at the University of Pretoria, were included in this
experiment. Each player completed a questionnaire of his or her tennis and
medical history. The players were then divided into a control group (22 subjects)
and an experimental group (20 subjects). All the subjects followed specific
exercise programmes; with the experimental group following an additional
programme five times a week based on certain scientific exercise principles. This
scientific programme focused on the prevention of shoulder injuries. Both groups
completed a series of physical scientific tests as discussed under Procedures in
Chapter 3.
To recapitulate, the purpose of this study was to determine whether following
specific scientific exercises would prepare the tennis player for the stresses of
the game and in this way reduce the occurrence of shoulder injuries throughout
the year. The primary objectives of the study was to determine whether a
specialized exercise programme, focusing on tennis dynamics, would minimize
the occurrence of shoulder injuries in junior tennis players. The secondary
objective was to determine the biomechanical working of the shoulder girdle in
the various tennis strokes and the influence of specific exercises on the
functioning of these muscles. In the light of the results discussed in Chapter 4,
the conclusions and recommendations are presented accordingly:
Results of the tests done to determine body composition showed a significant
difference (p<0.05) in the distribution of the lean body mass with the lean body
mass at T1 being lower than the lean body mass at T3 in the control group. For
the experimental group the fat percentage showed a significant decrease
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(p<0.05) from T1 to T3. The distribution of the muscle percentage at T1 was
significantly different (p<0.05) from the distribution of the muscle percentage at
T3 in the experimental group with the muscle percentage at T1 being lower than
the muscle percentage at T3.
Results of the tests done to determine muscle strength and endurance,
showed that there was a significant difference between the control and
experimental group for 1RM bench press (p<0.05) with the 1RM bench press
measurements at T3 being lower for the control group than for the experimental
group. Also, the 1RM bench press at T1 was lower than the 1RM bench press at
T3 in the experimental group. The experimental group showed a significant
increase from T1 to T3, peaking at T3 with the 1RM bench press. Statistically
significant differences were also found at the 5% level of significance between
the control and experimental group for maximum number of push-ups in 1
minute. The control group had a lower maximum number of push-ups in 1 minute
at both T2 and T3 than the experimental group, and the maximum push-ups in 1
minute at T1 were lower than the maximum push-ups in 1 minute at T3 in the
experimental group. The experimental group showed a significant increase from
T1 to T3 in the maximum number of push-ups in 1 minute. Statistically significant
differences were found at the 5% level of significance between the control and
experimental group for grip strength in both the dominant and non-dominant
hand. The grip strength of the dominant hand as well as the non-dominant hand
at T1 was lower than the grip strength of the dominant hand and the nondominant hand respectively at T3 in the experimental group. The grip strength of
the dominant hand at T1 was lower than the grip strength of the dominant hand
at T3 in the control group. The grip strength of the non-dominant hand at T1 was
lower than the grip strength of the non-dominant hand at T3 in the control group;
Results of the tests done to determine isokinetic muscle strength showed that
a statistically significant correlation (p<0.05) was found with regard to the
strength of the internal rotators of the non-dominant shoulder at T3, with the
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experimental group having a higher measurement than the control group. The
internal rotators and external rotators of both the dominant and non-dominant
shoulders were lower at T1 than at T3 in the experimental group (p<0.05). The
external rotators of the non-dominant shoulder at T1 were lower than the
external rotators of the non-dominant shoulder at T3 in the control group. The
strength of the flexor muscles for the non-dominant shoulder at T1 was lower
(p<0.05) than the strength of the flexor muscles for non-dominant shoulder at T3
in the experimental group. The strength of the elbow extensors for the dominant
as well as the non-dominant elbows was lower at T1 than at T3 in the
experimental group.
Results of the tests done to determine flexibility showed a statistically significant
difference with the internal rotators and external rotators of the dominant and
the non-dominant shoulders being lower at T1 than at T3 in the experimental
group. Also, the external rotators of the non-dominant shoulder of the control
group were lower at T1 than at T3.
Results of the tests done to determine posture showed that for the control group,
54.5% of players had scoliosis at T1 and 40.9% at T3, and for the experimental
group 55% of the players had scoliosis at T1 compared to the 30% at T3.
Although the percentage of players with scoliosis in both the control and
experimental groups showed a decrease from T1 to T3, the players in the
experimental group showed a larger decrease than those in the control group. In
the experimental group 38.5% of cases had a CM bend that was less than 5cm
in T1 and became more than 5cm in T3. In the control group 20% had a CM
bend less than 5cm in T1, which became greater than 5cm in T3. For the control
group 63.6% of the players’ shoulder heights were not level at T1, compared to
the 40.9% at T3. For the experimental group 55% of the players’ shoulder
heights were not level at T1, compared to 30% at T3. 63.6% of players in the
control group’s non-dominant shoulders were higher than the dominant shoulder
at T1, compared to the 40.9% of players at T3.
For the players in the
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experimental group, 50% had a higher non-dominant shoulder and 5% a higher
dominant shoulder at T1, compared to 25% and 5% respectively in the control
group, at T3. In the control group at T1, 63.6% of the group’s hips were not level,
compared to 40.9% at T3. For the experimental group at T1, 55% of the group’s
hips were not level, compared to 30% at T3. The percentage of players with
kyphosis in both the control and experimental groups decreased from T1 to T3.
In the control group, the percentage of players with kyphosis decreased from
63.6% at T1 to 46% at T3 and the experimental group decreased from 55% at T1
to 30% at T3. The percentage of players with lordosis in both the control and
experimental groups decreased from T1 to T3. In the control group, the
percentage of players with lordosis decreased from 50.0% at T1 to 40.7% at T3,
compared to the experimental group that decreased from 30% at T1 to 25% at
T3. Results of the tests done to determine the occurrence of injuries showed that
the players with no injuries in the control group stayed stable from T1 (54.5%) to
T2 (54.6%) where after it increased to 59.1% at T3. In the experimental group the
total players with no injuries stayed stable from T1 (55.0%) to T2 (55.0%) where
after it increased to 85% at T3. In the control group the percentage of players
with grade 1 and 2 injuries were 13.6% at T1, it increased to 18.2% at T2, and
decreased to 13.6% at T3. In the experimental group 15% of the players had
grade 1 injuries at T1. This percentage increased to 30% at T2 where after it
decreased to 15% at T3 again. The percentage of players with grade 2 injuries
remained stable at 10.0% from T1 to T2 in the experimental group. None of the
players had grade 2 injuries at T3. In the control group 9% of players had grade
3 injuries at T1, with none having it at T2 and T3. In the experimental group the
percentage of players with grade 3 injuries remained stable at 5.0% from T1 to
T2. None of the players had grade 3 injuries at T3. In the control group 4.5% of
players had grade 4 injuries at T1. This stayed more or less stable at T2 (4.6%)
and increased to 9.1% at T3. In the experimental group 10.0% of players had
grade 4 injuries at T1. None of the players had grade 4 injuries at either T2 or
T3. In the control group 4.5% of players had grade 5 injuries at T1, none had it at
T2, and 4.5% had it at T3. In the experimental group none of the players had
University of Pretoria etd – Gouws, K (2006)
182
grade 5 injuries at T1, T2 or T3. In the control group none of the players had
grade 6 injuries at T1 or T3. At T2, however, 4.6% of players had grade 6
injuries. In the experimental group 5.0% of players had a grade 6 injury at T1
and none of the players had this type of injury at T2 or T3.
Due to the results of the parameters obtained from the physiological tests, the
hypotheses of this study can thus be accepted. It is important to notice that the
two important aspects in preventing overuse injuries in tennis, showed a positive
improvement. The strength of the rotator cuff muscles, which are the primary
muscles preventing the humerus head from slipping out of the glenoid cavity
during play and which is active during all tennis strokes, improved significantly
from T1 to T3 in the experimental group (Priest & Nagel, 1976; Reece et al.,
1986; Roetert & Ellenbecker, 1998; Rubin & Kibler, 2002). Also, the programme
succeeded in strengthening the opposing muscle groups in both strength and
flexibility, minimizing muscle imbalances in the body (Burnham et al., 1993; Roy
et al., 1995; Kirshblum et al., 1997; Roetert & Ellenbecker, 1998; Salisbury et al.,
2003).
The hypotheses of this study have been successfully completed according to the
results obtained during the tests and the supporting literature. There are,
however, certain aspects in the physiology in tennis, as well as the differences
related to sex and ethnical groups that need further research (Salisbury et al.,
2003). The following recommendations are thus to expand on the improvements
and the scientific knowledge of tennis:
Î
a larger group of subjects must be used in order to determine the
differences between male and female players;
Î
two different groups can be used in order to determine ethnical
differences;
Î
more research needs to be done on the different stroke techniques that
the players use; and
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APPENDIX A
TENNIS RESEARCH PROJECT QUESTIONNAIRE
A Biokinetic Approach to the Prevention and Rehabilitation
of
Shoulder Injuries in Tennis Players
-----------------------------------------------------------------------------------------------------------First Name
Surname
ID
Age
Gender Male Female
Tel
/
-------------------------------------------------------------------------------------------Medical History
1. Have you ever had any bone or muscle injuries before?
Yes No
ÖIf yes, what kind of injury:__________________________________________
________________________________________________________________
_________________________________Date: __________________________
2. Do you currently suffer from any kind of injury?
Yes No
ÖIf yes, what kind of injury?__________________________________________
________________________________________________________________
________________________________________________________________
3. Have you ever had any operations done before?
Yes No
ÖIf yes, what kind of operation?_______________________________________
ÖDate of operation / /
4. Do you suffer from asthma?
Yes
No
5. Do you suffer from epilepsy?
Yes
No
Tennis History
1.
2.
3.
4.
5.
6.
7.
8.
At what age did you start playing tennis?
At what age did you start playing serious competitive tennis?
How long have you been at the Center of Excellence or ITF? _____________
In the last year, how many hours did you spend on the court a day?
In the last year, how many days did you play tennis a week?
Have you ever trained in a gym before?
Yes
No
Have you ever followed fitness programmes on-court?
Yes
No
What tension is your racquet strung? _______________________________
--------------------------------------------------------------------------------------------
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Purpose of the research: This study is submitted in fulfillment of the degree
DPhil (Biokinetics) (Doctoral degree). The results of this research will be used to
develop conditioning programmes for tennis players that will help to minimize the
occurrence of injuries during the year and therefore maximize performance of the
tennis player. Also, the rehabilitation programme aims to get the injured player
back on court as quickly as possible!
Conditions of the research:
• It will be expected of the participants to stay on the training programme for the
duration of nine months;
• All participants will complete 3 Scientific Fitness Tests in 3-monthly intervals;
• It will be expected from the participants to co-operate with the Biokineticists in
charge of the study;
• The training programmes will be incorporated into the normal training
schedule at the Center of Excellence and the ITF. The experimental group will
have 3 additional training sessions of 20 minutes a week for specific shoulder
strengthening exercises.
I, ______________________________, agree to take part in the research
project according to the above mentioned conditions.
Signature: ___________________________
Date: ________________
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APPENDIX B
POSTURAL ANALYSIS
for
TENNIS PLAYERS
NAME _______________________ DOM TENNIS HAND: R ‫ ٱ‬L ‫ٱ‬
-----------------------------------------------------------------------1. Shoulder height:
Right high ‫ٱ‬
Level ‫ٱ‬
2. Hip height:
Level ‫ٱ‬
Left high ‫ٱ‬
Right high ‫ ٱ‬Left high ‫ٱ‬
3. Scapula:
Symmetric ‫ٱ‬
R- prominence ‫ ٱ‬L- prominence ‫ٱ‬
4. Kifosis:
Normal ‫ٱ‬
Severe ‫ٱ‬
5. Lordosis:
Normal ‫ٱ‬
Severe ‫ٱ‬
6. Scoliosis:
• Visual:
Convecs to left ‫ٱ‬
Convecs to right ‫ٱ‬
• Thoracic spine motion: (Schrober)
< 5cm ‫ٱ‬
5cm ‫> ٱ‬5cm ‫ٱ‬
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FLEXIBILITY
1. Shoulder Internal Rotation:
R _________
L __________
2. Shoulder External Rotation:
R ________
L __________
3. Shoulder flexion:
__________cm
4. Shoulder Extension:
__________cm
-------------------------------------------------------------------------------------------FUNCTIONAL STRENGTH
1. Maximum Push-ups in 1 minute: ___________
2. Grip Strength:
R __________
L __________
-------------------------------------------------------------------------------------------ISOKINETIC STRENGTH
1. Shoulder flexion/extension:
2. Shoulder internal/external rotation
3. Shoulder abduction/ adduction
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APPENDIX C
TESTING PROFORMA
1. Questionnaire
2. Postural analysis
3. Body Composition
•
Height
•
Weight
•
Fat percentage
a. Skinfolds:
Î Biceps:
Î Triceps:
Î Subscapula:
Î Supra iliac:
Î Para umbilicus:
Î Medial thigh:
Î Calf :
b. Girths:
Î Biceps relaxed:
Î Biceps flexed and tense:
Î Fore arm girth:
Î Wrist girth:
Î Chest girth:
Î Waist girth:
Î Hip girth (Gluteal):
Î Thigh girth
Î Calf girth:
Î Ankle girth:
c. Obtaining Breadths:
Î Biacromial breadth:
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Î Transverse chest width: excursion (end tidal).
Î Biiliocristal breadth:
Î Anterior/posterior chest depth:
ÎHumerus width:
Î Femur width:
4. Flexibility
a. Shoulder internal and external rotation:
b. Shoulder flexion and extension:
5. Functional strength
Î Maximum push-ups in 1 minute:
6. Isokinetic strength
Î Shoulder flexion & extension:
60º:
3 Warm-ups @ 50%, 75% and 100% respectively;
5 maximal efforts recorded.
180º:
3 Warm-ups @ 50%, 75% and 100% respectively;
20 maximal efforts recorded
Î Shoulder abduction & adduction:
60º:
3 Warm-ups @ 50%, 75% and 100% respectively;
5 maximal efforts recorded.
180º:
3 Warm-ups @ 50%, 75% and 100% respectively;
20 maximal efforts recorded
Î Shoulder internal & external rotation:
60º:
3 Warm-ups @ 50%, 75% and 100% respectively;
5 maximal efforts recorded.
180º:
3 Warm-ups @ 50%, 75% and 100% respectively;
20 maximal efforts recorded
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APPENDIX D
SHOULDER STRENGTHENING
PROGRAMME
Reps Sets
EXERCISE
1)Bench Press / Dumbell Bench Press
2)Dumbell side raises (fast up & slowly down)
3)Dumbell / barbell biceps curls (slowly down)
4)Lie on back on bench: Straight arm flexion &
extension with dumbell
5)Wrist deviation (thumb up – flex hand up &
down
6)Arm 90º horizontal in front: rotate arm in and
out
7)Wrist Curls
8)Reverse wrist curls
9)Triceps push down / Dips
10-12
10
10
10
3
3
3
2
12
2
12
2
12
12
10-15
2
2
3
Weight
ELASTIC BAND PROGRAMME
EXERCISE
Protraction: Straight arm in front-push shoulder forward
(elastic behind you)
Reps
Sets
15
2
Retraction: Straight arm in front-pull shoulder
back (elastic in front of you)
90º shoulder rotation: (work in both directions)
• elbow against side: rotate hand in & out
• elbow beside shoulder – rotate hand up &
down
• elbow in front of shoulder – hand up & down
15
2
10/1
0
10/1
0
10/1
0
12
12
12
12
2
2
2
Biceps curls (slowly down)
Triceps extension
Front raises
Face the elastic-palm back – push straight arm
back
2
2
2
2
Weight
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APPENDIX E
ADDITIONAL FLEXIBILITY EXERCISES
b. Hip and leg stretches:
i)
Figure 4 hamstrings stretch: (Figure 62)
Focus:
Hamstrings:
Start:
Sit with one leg stretched out in front with the knee straight and the
toes pointing upwards. Bend the other knee and place the sole of
the foot against the knee of the straight leg.
Action:
Keep the back erect and the knee as straight as possible while you
reach forward with both hands trying to touch the toes (Burnham et
al., 1993; Roetert & Ellenbecker, 1998).
ii)
Hamstring stretch: (Figure 63)
Focus:
Hamstrings and gluteal muscles
Start:
While lying on your back, bend the leg that you want to stretch to
90º at the hip. Support the bent leg by grasping both hands behind
the knee, keeping the opposite leg straight.
Action:
Straighten the lifted leg and raise it towards the trunk. The hands
can be used to gently increase the stretch. Also, to increase the
stretch, point the toes towards the face (Roetert & Ellenbecker,
1998).
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Figure 62: Figure 4 hamstrings stretch.
iii)
Figure 63: Hamstring stretch.
Hamstring super stretch: (Figure 64)
Focus:
Hamstrings and calf muscles.
Start:
Place the one leg on an object approximately waist height.
Action:
In a slow and smooth motion bend forward at the waist, bringing
your trunk toward your thigh. Bending the toes toward your face will
increase the stretch (Burnham et al., 1993; Roetert & Ellenbecker,
1998).
iv)
Stork quadriceps stretch: (Figure 65)
Focus:
Quadriceps and the hip flexors
Start:
Stand on one leg. Bend the opposite knee and grasp the foot or
ankle.
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Action:
Keep the back straight and buttocks tucked in. Bend the knee and
bring the foot toward the buttocks until the knee points toward the
floor. Take care not to twist the knee (Roetert & Ellenbecker, 1998).
Figure 64: Hamstring super stretch.
v)
Figure 65: Stork quadriceps stretch.
Prone quadriceps stretch: (Figure 66)
Focus:
Quadriceps and hip flexors.
Start:
Lie flat on your stomach.
Action:
Bend one knee to bring the foot toward the buttock and grasp the
foot or ankle with the hand on the same side of the body. Pull the
foot directly toward the buttock without twisting the knee (Roetert &
Ellenbecker, 1998).
vi)
Groin stretch: (Figure 67)
Focus:
Groin and the inner thigh muscles.
Start:
Stand with your feet shoulder width apart and with your hands on
your hips.
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Action:
With the toes pointing slightly outwards, slowly bend the one knee
until you feel a stretch in the groin. Roll your weight slowly to the
inside of the opposite foot (Burnham et al., 1993; Roetert &
Ellenbecker, 1998).
Figure 66: Prone quadriceps stretch.
v)
Figure 67: Groin stretch.
Seated groin stretch: (Figure 68)
Focus:
Groin and the inner thigh muscles
Start:
Sit with the soles of your feet touching each other, knees pushed
outwards with your hands holding your toes.
Action:
Bending from the hips, pull yourself forward, bringing the chest to
the feet. Keep the back straight and gently push the knees toward
the ground with your elbows (Roetert & Ellenbecker, 1998).
vi)
Hip twist: (Figure 69)
Focus:
Lateral hip muscles and the lower back.
Start:
Lie on your back with knees bent and feet flat on the floor. Place
the arms outwards at the side in order to stabilize the upper back.
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Lift the left leg and place the left ankle on the outside of the right
knee.
Action:
Use the left leg to pull the right leg toward the floor until you can
feel a stretch along the outside of the hip or lower back. The upper
back and shoulders must remain flat on the floor at all times. The
right leg should not touch the floor, but be stretched within your
limits (Burnham et al., 1993; Roetert & Ellenbecker, 1998).
Figure 68: Seated groin stretch.
vii)
Figure 69: Hip twist.
Piriformis stretch: (Figure 70)
Focus:
Piriformis muscle
Start:
Lie on your back with the left leg bent and the right ankle resting
just above the left knee.
Action:
Keeping the right knee pointing outwards, slowly bring the left knee
toward the chest. You should feel the right buttock stretching
(Roetert & Ellenbecker, 1998).
viii)
Iliotibial band stretch: (Figure 71)
Focus:
Iliotibial band
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Start:
Stand with your right hand against the wall, the right leg
approximately 1 meter from the wall and the left leg crossed over
the right leg.
Action:
Gently start pushing the right hip toward the wall. In order to
intensify the stretch, you could stand further away from the wall
(Burnham et al., 1993; Roetert & Ellenbecker, 1998).
Figure 70: Piriformis stretch.
ix)
Figure 71: Iliotibial band stretch.
Calf stretch: (Figure 72)
Focus:
Gastrocnemius and soleus.
Start:
Stand facing a wall or fence with one leg 0.5 to 0.75m behind the
other with all the toes pointing forward.
Action:
a. Bend the front knee and lean forward with the trunk and hips,
keeping the back leg straight, the heel on the floor and the back
erect.
b. Repeat the stretch as for (a) but bend the back knee slightly,
keeping the heel on the floor (Roetert & Ellenbecker, 1998).
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c. Trunk stretches:
i)
Knee to chest flex: (Figure 73)
Focus:
Lower back and gluteal muscles
Start:
Stand upright with your feet shoulder width apart.
Action:
Bend the one leg and grasp the lower leg below the knee. Keeping
the back straight, slowly pull the knee to the chest (Roetert &
Ellenbecker, 1998).
Figure 72: Calf stretch.
ii)
Figure 73: Knee to chest flex.
Double knee to chest flex: (Figure 74)
Focus:
Lower back and gluteal muscles.
Start:
Lie on your back with both knees bent.
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Action:
Grasp the lower legs just below the knees and bring the knees
toward the chest (Burnham et al., 1993; Roetert & Ellenbecker,
1998).
.
iii)
Spinal twist (Figure 75):
Focus:
Lower back and hip rotators.
Start:
Sit with the left leg slightly bent in front of you. Place the right ankle
on the outside of the left knee.
Action:
Place the left arm around the right knee and then slowly turn the
shoulders and the trunk to the right. Look over the right shoulder
(Roeter & Ellenbecker, 1998).
Figure 74: Double knee to chest flex.
Figure 75: Spinal twist.
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