An Ergonomic Study of Muscular Fatigue during Ironing Clothes with

An Ergonomic Study of Muscular Fatigue during Ironing Clothes with
© Kamla-Raj 2008
J. Hum. Ecol., 24(1): 31-34 (2008)
An Ergonomic Study of Muscular Fatigue during Ironing
Clothes with Selected Irons
P. Aujla, P. Sandhu* and R. Kaur
Department of Family Resource Management, Punjab Agricultural University, Ludhiana,
Punjab, India
KEYWORDS Energy. Hand Grip. Muscular Fatigue. Posture. Stress
ABSTRACT Muscular fatigue (hand grip) and body pains experienced during ironing of clothes in standing posture
on 82 cms high board with selected irons of different weights were measured on 6 female subjects. Results showed
that muscular fatigue and body pains while ironing with light weight iron (0.77 kgs) were found significantly less as
compared to other selected irons. Muscular fatigue and body pains was found to be significantly higher while ironing
with heavy weight iron (2.92 kgs) as compared to light weight iron and steam iron (1.29kgs). Thus ironing clothes
with light weight iron causes minimum stress to body and using heavy weight iron is found to be most taxing
to human body.
INTRODUCTION
Owing to technological development, a large
variety of automatic electric irons have become
available to homemaker almost wiping out
traditional charcoal iron and non electric ones.
These irons conserve energy, reduce time and
labour and give job satisfaction (Dhantyagi,
1996). Electric irons are regularly used by 96.6
percent urban and 80.8 percent rural residents of
Ludhiana district (Dhablania, 1992). However
efficiency of different electric irons may vary, due
to its design, weight, size and shape. In fact
Grewal (1975) in her study on performance of
automatic electric irons has found that weight of
2.75 Kg. is more appropriate than 3.43 Kg. Ironing
clothes is however considered moderately heavy
household activity which demands lot of
muscular effort (Jindal, 1974). Many homemakers
perform this activity without realising the extra
muscular effort involved due to weight of irons
which may result in higher muscular fatigue and
body pains. Such static muscular effort can
damage the intervertibral discs (Guyton, 1988).
Hence it becomes important to assess muscular
stresses caused by irons of different weights
while ironing in standing posture, so as to isolate
more fatiguing models of irons. Present study was
therefore, undertaken with following objectives:
1. To assess muscular fatigue and body pains
while ironing in standing posture with irons
of varying weights.
*Corresponding author: Dr. Pushpinder Sandhu
E-mail: spushi@rediffmail.com; pushi12@yahoo.com
2. To recommend the best iron on the basis of
selected parameters for household use.
METHODOLOGY
Selection of Subjects: 6 female students of
mean age 22.16 ± .5 years, mean weight 51.00 ±
1.5 kg, mean height 152.41 ± 2 cms, mean elbow
height 94.00 ± 1cm and mean body surface area
1.45±.02 sq.m., and basal metabolic rate, respiration and heart rate within normal physiological
range were selected for the study.
Selection of Irons: Three automatic electric
irons found commonly used at domestic level
were selected viz light weight iron (.77 kgs) heavy
weight iron (2.92 kgs) and steam iron (1.29 kgs).
Standardization of Experiment: Ironing was
done in standing posture at 82 cms height as
recommended by Jindal (1974). A fixed load of 21
garments, mixed lot of cotton, wool, silk, blended
and synthetic fabrics, were ironed by subjects
by following a standardized procedure for 60
minutes.
Measurement of Muscular Fatigue: The
grip strength of left right and both hands was
measured with the help of gripdynamometer. It
consisted of a handle for hand grip connected
with a spring to a position on a marked dial. The
subject was asked to pull the grip handle with
right and left hand separately and then both
hands together and the reading given on the dial
in Kgs was noted down separately was taken
before and after the ironing activity. The grip
strength was calculated in terms of percentage
decrease in grip strength (grip fatigue) by
P. AUJLA, P. SANDHU AND R. KAUR
32
subtracting grip strength during work (sw) from
grip strength during rest (Sr)
Percent decrease in grip strength =
Sr - sw
x 100
Sr
Body Pains Experienced by the Experimental Subjects: A questionnaire containing
questions related to feelings of tiredness on
different body parts of experimental subjects
with selected irons was also scored from the
degree of no pains to sever pains. It was repeated
thrice for each iron with each subject.
Statistical Analysis of Experimental Data:
Data on different parameters were compiled and
tabulated. Analysis of variance (ANOVA) test
was used to test the significance of differences.
Calculated value of variance ratio ‘F’ was
compared with the corresponding table value.
The critical difference was calculated with the
following formula:
C.D. =
2 X Error mean
sum of squares
X t Value at 0.05/0.01 level
No. of
replications
compared to left hand with the selected irons. This
may be due to habitual use of right hand for ironing
by all the subjects as compared to left hand. These
findings are in accordance with the findings of
Oberoi et al. (1987) who reported the muscular
fatigue of right hand was more as compared to lefthand.
Table 1: Mean percentage decline in grip muscular
strength (kgs) with selected irons after ironing
of clothes.
Irons
Mean percentage decline in grip muscular
Strength (kgs) with selected irons (rest=100)
Right hand
Light
Steam
Heavy
7.72
15.60
24.07
Both hands
12.63
15.15
23.65
9.01
11.92
17.93
Table 2: Analysis of variance of grip muscular
strength (Kgs) of right, left, and both hands after
ironing with selected irons.
Source of
variation
Degree Sum
Mean F-ratio
of
of
of
freedom squares sum
squares
RESULTS AND DISCUSSIONS
Arm Muscular Strength: The mean values
of percentage decrease of the muscular strength
for both the hands independently (right hand,
left hand) and together (both hands) are
presented in Table1. It indicates that the minimum
decrease occurred while ironing of the clothes with
light weight electric iron 7.72 kgs, 12.63 kgs, 9.01
kgs for right, left and both hands respectively.
Analysis of variance (Table 2) for both the hands
independently and together and the differences of
percent decline in the muscular strength of both
the hands independently and together while
ironing clothes with selected irons were statistically
significant. The mean differences of percent decline
in grip strength after ironing the clothes revealed a
significant difference within the selected irons. The
maximum significant difference of right hand (Table
3) was observed between heavy weight and light
weight iron viz 16.35 kgs followed by difference
between heavy weight and steam iron (8.47 kgs)
and least difference was recorded between the
steam iron and light weight iron (7.88 kgs). The
difference of mean, values between steam iron
and light weight iron were found to be nonsignificant for both the hands (Table 3). The data
presented in Table 1 also indicate that the percent
decrease in grip strength of right hand was more as
Left hand
a) Right Hand
Between irons
3
829.40
276.46
Within irons
Total
b) Left Hand
Between irons
20
23
323.77
1153.17
16.18
3
415.64
138.54
Within irons
Total
c) Both Hands
Between irons
20
23
767.16
1182.77
38.58
3
704.1
17.08*
3.59 -
237.7
20.62*
Within irons
20
227.78
Total
23
931.88
11.38
*Significant at P < 0.05 level; - Non significant; C.D
= 3.98 at P < 0.05 and 5.41 at P < 0.01
Table 3: Difference of values of mean percent
decrease in right hand and both hands grip strength
with selected irons after ironing of clothes.
Heavy
a) Right Hand
Heavy
Light
Steam
b) Both Hands
Heavy
Light
Steam
Light
Steam
-
16.35**
-
8.47**
7.88**
-
-
8.93
-
6.01
2.91
-
* Significant at P < 0.05 level; ** Significant at P < 0.01 level
AN ERGONOMIC STUDY OF MUSCULAR FATIGUE DURING IRONING CLOTHES
Table 4: Scores of body pains after ironing with
different irons as experienced by subjects.
Body
parts
Forehead
Neck
Back
Arms
Shoulder
Hand
Upper leg
Lower leg
Feet
Steam
iron
5.0
5.0
5.0
4.5
4.8
4.7
3.5
3.2
4.2
Total
39.9
Average
4.43
Light
weight iron
5.0
5.0
5.0
4.8
5.0
4.8
3.5
3.2
4.2
40.5
4.5
Heavy
weight iron
5.0
5.0
5.0
4.0
2.3
3.7
3.5
3.2
4.2
35.9
3.98
Table 5: A comparative evaluation of different
selected irons during ironing of clothes with
respect to grip muscular strength
Grip
Steam Light
musiron weight
cular
iron
strength
Right
hand
(kgs)
Left
hand
(kgs)
Both
hand
(kgs)
Heavy
weight
iron
Steam C. D. at
iron 5% 1%
15.06 7.72
24.07
15.6 4.75 6.45
——————————
——————————
————————
15.15 12.63 23.65
15.15 ==================
===================
=================
11.92 9.01
17.93
11.92 3.98 5.41
———————————
=================
=================
———— line joining the values show non - significant
differences..
===== line joining the values show significant
differences at P<0. 01 level.
Body Pains as Experienced by the Experimental Subjects During Ironing: The mean
scores of feelings of body pains while ironing
by the subjects are given in Table 5. Five-points
scales was chosen for the scoring of body pains
from no pains to severe pains. Higher the Score,
lesser the pains and vice-versa was experienced
by the experimental subjects during ironing with
selected irons. Slight pains were experienced
while ironing with steam iron in arm, hand and
shoulder with a mean score of 4.5, 4.7 and 4.8
respect-lively. As compared to steam iron less
pain was experienced with the light weight iron
in arm and hand with a mean score of 4.8 for each
and absolutely no pain was experienced in the
shoulders. It might be due to the lightest weight
of the iron, much pressure was not experienced
by the subjects, on the shoulders. Highest
33
degree of discomfort was experienced in the arm,
hand and shoulder while ironing with the heavy
weight iron with mean scores of 4.0, 3.7 and 2.3,
owing to its heaviest weight and lowest
temperature setting. The activity was performed
while standing so the feeling of discomfort was
experienced in upper leg, lower leg and feet with
all the three irons. The mean scores for upper
leg, lower leg and feet are 3.5, 3.2, and 4.2 for
each iron respectively. The pain in the legs was
experienced in the lower region, resulting in the
reduced circulation of the blood. There was pain
in the feet because of accumulation of the blood
in the feet (Bridger, 1995). It was further observed
that the severity of the pain was related to the
amount of work (Grandjean, 1973).
Comparative Evaluation of Best Iron for
Ironing Clothes in Standing Posture: Comparative evaluation of different iron was done on
the basis of physiological stresses grip Muscular
strength of right left and both hands of body to
find out best iron which would be least taxing.
Table 5 indicates that using light weight iron (.77
kgs) to iron clothes averaged significantly lower
values ofgrip muscular strength of right, left and
both hands, when compared to using steam iron
(1.29 kgs) and heavy weight iron (2.92 kgs). On
the basis of this comparison light weight iron
(0.77 kgs) was found to be best among other
selected irons because it has lowest value of grip
muscular strength of right left and both hands.
It was also found that steam iron accounted for
lower increase in heart rate and respiration
frequency as compared to use of heavy weight
iron. It can thus be concluded that light weight
iron is best followed by steam iron whereas heavy
weight (2.92 kgs) iron was rated most taxing for
human body and should not be adopted to use
commonly in households.
CONCLUSIONS
It can be thus concluded that muscular
fatigue and body pains while ironing clothes by
light weight iron (.77 kgs) was found significantly
low as compared to other selected irons. The
increase in all the parameters while using steam
iron (1.29 kgs) and heavy weight iron (2.92 kgs)
was found to be significantly higher than light
weight iron. Results of comparative evaluation
for all selected irons while ironing selected
clothes revealed that light weight iron (.77 kgs)
is best suitable because it is least taxing to body
P. AUJLA, P. SANDHU AND R. KAUR
34
as compared to other irons. Heavy weight iron is
rated most taxing to body while ironing clothes.
REFERENCES
Bridger, R. S.: Introduction to Ergonomics. McGraw
Hill Inc., New York (1995).
Dhablania, P.: Trends in the Possession and Use of Time
and Energy Conservation Devices by Rural and
Urban Families. M. Sc. Thesis, Punjab Agricultural
University, Ludhiana (1992).
Dhantyagi, S.: Fundamentals of Textiles and Their Care.
5 th Edition. Orient Longman Limited, New Delhi.
Pp. 207-210 (!996).
Grandjean, E.: Ergonomics of the Home. Taylor and
Francis Ltd. London (1973).
Grewal, C. S.: A Study of Performance of Automatic
Electric Irons. M. Sc. Thesis, Punjab Agricultural
University, Ludhiana (1974).
Guyton, A.L.: Circulatory Physiology: Cardiac Output
and its Regulation. W.B. Saunders Philadelphia,
Pp.312, 326-365 (1988).
Jindal, V.: Comparison of Physiological Costs While Ironing
During Sitting and Standing Positions. M. Sc. Thesis,
Punjab Agricultural University, Ludhiana (1974).
Obreoi, K., Sharma, K. K. and S.S. Miglani, S. S.:
Ergonomic assessment of household activities.
Journal Maharashtra Agri. Univ., 12: 364-366
(1987).
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