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This study was conducted in Iranian carpet industry to determine the prevalence of upper limb problems associated with hand tools design, investigate the design of hand tools currently used in carpet weaving operation, and design/redesign the tools based on anthropometric dimensions and ergonomic principles. This study consisted of two phases. In the first phase, 862 weavers from three Iranian provinces participated. A questionnaire consisting of personal details, Nordic Questionnaire for upper limbs and a table for anthropometric dimensions of hand was used to collect the required data. In the design phase, the study focused on designing/redesigning the weaving comb, knife and scissors as the most common tools in carpet weaving operation. Based on the first phase results, three prototypes of the hand tools were made in this phase. Usability test was conducted to assess comfort and applicability of the designed hand tools and the weavers’ perceptions. Ten experienced weavers participated in this test. Statistical analyses revealed significant differences between the scores of the old and the new designed tools. There was a significant preference towards the comfort and applicability of the prototypes (p<0.01). The new ergonomically designed weaving hand tools were found to be applicable and acceptable by the carpet weavers.Relevance to industryIn hand-woven carpet industry as a small-scale industry, hand tools are widely used. As extensive use of hand tools may play an important role in the development of upper limb musculoskeletal disorders (MSDs), ergonomic improvements in the carpet hand tools may promote health and safety among carpet weavers.
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International Journal of Industrial Ergonomics 37 (2007) 581–587
Ergonomic design of carpet weaving hand tools
Majid Motamedzade
a,
, Alireza Choobineh
b
, Mohammad Amin Mououdi
c
,
Shirazeh Arghami
d
a
Occupational Health Department, School of Health, Hamedan University of Medical Sciences, Hamedan, Iran
b
School of Health, Shiraz University of Medical Sciences, P.O. Box 71645-111, Shiraz, Iran
c
School of Health, Mazandaran University of Medical Sciences Sari, Iran
d
School of Health, Zanjan University of Medical Sciences, Zanjan, Iran
Received 3 December 2005; received in revised form 26 February 2007; accepted 7 March 2007
Available online 9 May 2007
Abstract
This study was conducted in Iranian carpet industry to determine the prevalence of upper limb problems associated with hand tools
design, investigate the design of hand tools currently used in carpet weaving operation, and design/redesign the tools based on
anthropometric dimensions and ergonomic principles. This study consisted of two phases. In the first phase, 862 weavers from three
Iranian provinces participated. A questionnaire consisting of personal details, Nordic Questionnaire for upper limbs and a table for
anthropometric dimensions of hand was used to collect the required data. In the design phase, the study focused on designing/redesigning
the weaving comb, knife and scissors as the most common tools in carpet weaving operation. Based on the first phase results, three
prototypes of the hand tools were made in this phase. Usability test was conducted to assess comfort and applicability of the designed
hand tools and the weavers’ perceptions. Ten experienced weavers participated in this test. Statistical analyses revealed significant
differences between the scores of the old and the new designed tools. There was a significant preference towards the comfort and
applicability of the prototypes (po0.01). The new ergonomically designed weaving hand tools were found to be applicable and
acceptable by the carpet weavers.
Relevance to industry
In hand-woven carpet industry as a small-scale industry, hand tools are widely used. As extensive use of hand tools may play an
important role in the development of upper limb musculoskeletal disorders (MSDs), ergonomic improvements in the carpet hand tools
may promote health and safety among carpet weavers.
r2007 Elsevier B.V. All rights reserved.
Keywords: Carpet weaving; Hand tools; Ergonomic design; Upper limbs musculoskeletal disorders
1. Introduction
In a large number of industrial occupations, hand tools
are primary tools. A major concern of these industries is
the high percentage of injuries that occur annually (Lewis
and Narayan, 1993). In many occupations, some of the
major causes of work-related disorders and diseases are
linked to the use of hand tools. It has been shown that tool
design may play an important role in the development of
work-related problems in the upper limbs (Lewis and
Narayan, 1993;Kadefors et al., 1993). The relationship
between occupational musculoskeletal disorders (MSDs)
and the use of hand tools is well known (Armstrong et al.,
1982;Aghazadeh and Mital, 1987). Poor design of hand
tools may result in cumulative trauma disorders (Arm-
strong, 1986). Occupational accidents can be linked directly
to the use of specific hand tools as well (Sperling et al.,
ARTICLE IN PRESS
www.elsevier.com/locate/ergon
0169-8141/$ - see front matter r2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.ergon.2007.03.005
Corresponding author. Fax: +98 811 8255301.
E-mail addresses: motamedzade@yahoo.com (M. Motamedzade),
alrchoobin@sums.ac.ir (A. Choobineh),mououdi@yahoo.com
(M.A. Mououdi),arsh42@yahoo.com (S. Arghami).
1993). Ergonomically well-designed hand tools may
reduce the risk of occupational injuries of the upper limbs.
They also provide comfortable work for the users and give
high product quality to the consumers (Sperling et al.,
1993).
Carpet hand weaving is a common practice in different
countries such as Iran, China, Turkey, India, Pakistan,
Russia, Egypt, Nepal and Afghanistan where intense use of
hand tools is observed (Choobineh et al., 2004a). Upper
limbs problems are prevalent as work-related MSDs
among weavers. Kutluhan et al. (2001) believed that
hand-made carpet weavers were exposed to varying degrees
of repetitive and forceful hand and wrist motions with non-
ergonomic hand tools and they seemed to be at increased
risk of developing upper limbs musculoskeletal symptoms
and carpal tunnel syndrome (CTS). They concluded that
weaving was a high-risk profession for upper extremity
repetitive strain and CTS. Radjabi declared that constant
tying of knots with non-ergonomic hand tools might result
in swollen finger joints, arthritis and neuralgia, causing
permanent deformation of the fingers (Radjabi, 1983).
Researches have proved that in weaving operation because
of continuous use of wrists, fingers and repetitive move-
ments, the risk of wrist and hand soft tissue, particularly
median nerve, injuries are high (Senveli et al., 1987;Tan
and Tan, 1998;Budak et al., 2001).
In carpet weaving operation, more than 10 different
kinds of hand tools are applied among them weaving
comb, knife and scissors are the most commonly used.
Basically, these are cheap tools made by blacksmiths using
traditional and primitive technology from unsuitable
materials and workmanship that noticeably contribute to
accidents. They are traditionally designed and no ergo-
nomics principle is applied in their structures (Choobineh
et al., 2004b).
As the use of hand tools may play an important role in
the development of disorders and accidents, it is obvious
that improvements in the design of hand tools are essential
for promoting professional users’ health, particularly
where there is intensive exposure.
As given above, the present study was conducted in
Iranian carpet industry to determine the prevalence of
upper limb problems associated with hand tools design,
investigate the design of hand tools currently used in carpet
weaving operation and, if necessary, redesign the tools
based on anthropometric characteristics of weavers’ hands
and ergonomics principles.
2. Materials and methods
This study consisted of two phases, which are described
separately.
2.1. Phase 1: field study
In this phase, weavers’ individual characteristics and
upper limb musculoskeletal symptoms in active weaving
workshops in rural and urban districts of nine cities in
three Iranian provinces including Eastern Azarbayejan
(north–west of Iran), Isfahan (central of Iran) and Kerman
(south–east of Iran) were surveyed and weaving hand tools
were studied. In each province, up to 300 weavers were
randomly selected from the corresponding list of work-
shops. Totally, 862 weavers participated in this phase of
study. A questionnaire was applied to collect required data
from each weaver. The questionnaire consisted of three
parts including; (a) personal details, (b) Nordic Muscu-
loskeletal Questionnaire for upper limbs (Kuorinka et al.,
1987), and (c) a table for anthropometric dimensions of
hand.
All workshops were visited and the questionnaires
were completed by interview. Upon questionnaire comple-
tion, anthropometric dimensions of weavers’ hands were
measured with direct method using a digital caliper by
trained field researchers. Necessary data on weaving
hand tools design and application in carpet weaving
operation were provided by photography and videotaping
techniques.
2.2. Phase 2: hand tool design
In the design phase, based on the results of the first
phase, designing/redesigning weaving comb, knife and
scissors as the most commonly used hand tools in carpet
weaving operation were in central attention. In this phase,
the following procedure was followed:
Providing a collection of carpet weaving hand tools
currently used in weaving operation.
Studying carpet weaving hand tools during work
for considering design/redesign requirements and deter-
mining their specifications including weight, texture,
handle shape and hand posture during hand tools
application.
Developing new models of hand tools according to hand
anthropometric characteristics of the weavers and
ergonomic design principles.
Making prototypes.
Testing the prototypes based on a usability test
protocol.
Redesigning the prototypes regarding the results of
usability test.
Handles were found to be the critical components of the
carpet weaving tools, particularly for weaving combs and
knives. For designing handle shape and length, the hand
anthropometric database and weaving practice were the
basic considerations.
Design principles: Physical factors taken into
consideration in developing new models are described
below:
For greatest comfort of use and least stress, the tool
handle should be oriented so that, while working, the
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hand and the forearm are aligned. Since the shape of the
tool handle will affect the posture used to hold it, the
shape of the handle is a primary factor which can be
used to reduce or eliminate fatigue in the user (Winston
and Narayan, 1993).
The major muscles, which flex the fingers and generate
grip force are located in the forearm. These muscles have
long tendons that span the wrist joint. Thus, the
gripping capability of the fingers is affected by the
position of the wrist. Frequent use of hand tools with
the wrist in a bent position can cause inflammation,
chronic pain, and possible permanent injury both to
synovial sheats, protecting the tendons of the wrist and
the median nerve passing through the wrist (Tichauer,
1966).
The cross-sectional configuration of the tool handle
directly affects the operator’s performance and health.
The forces generated during use should be distributed
on as large a pressure area of the palm as possible
(Winston and Narayan, 1993).
Recesses such as finger grooves should not be provided
because of the wide variations in finger anthropometry
in the population. In particular, a person with large
fingers may create compressive forces on the lateral
surfaces of the fingers, which are areas abundant in
superficial nerves and veins (Winston and Narayan,
1993).
If a tool has a short handle that does not span the
breadth of the palm, high forces are created at the center
of the palm. Thus, the tool handle should be designed to
extend beyond the hand when gripped (Winston and
Narayan, 1993).
Sharp edges and corners may cause cuts, bruises, or
abrasions. Hence, one should seek to eliminate such
hazards by rounding edges and corners with as large a
radius as possible.
Prototype testing: Usability test was conducted to assess
comfort and applicability of the designed hand tools and
the weavers’ perceptions. Five experienced male and five
experienced female weavers, having mean age 29.7 years
[SD ¼7.4], mean weight 65 kg [SD ¼7.3], mean stature
167.8 cm [SD ¼4.2], and mean weaving experience six
years [SD ¼5.2] participated in this stage. In the usability
study, the hand tools evaluation checklist, developed by
Dababneh et al. (2004) was applied and the related scores
were calculated (maximum score ¼100). The checklist was
modified according to carpet weaving hand tools features
(see Appendix A).
In this stage, each weaver took part in three trials of
30 min. In each trial a certain tool is assessed, in which the
weaver performed weaving tasks using both traditional
tool and the prototype with the same sharpness. Upon
completion of the trial, the checklist was presented to the
weaver and her/his perception was measured. Based on the
results, the ergonomic score for each tool was, then,
calculated.
The data on weavers’ perceptions were statistically
tested to determine differences between the traditional
and new tools. Perceptions were tested by Wilcoxon
signed-rank test. The level of significance for statistical
tests was 0.05. Statistical analyses were performed using
SPSS 10.
3. Results
3.1. Phase 1
Table 1 shows the personal characteristics of the carpet
weavers studied in three provinces. The majority of
weavers were female (74%). Table 2 presents the pre-
valence of MSDs symptoms in both dominant and non-
dominant upper extremities in the upper limbs of the
weavers during the last 12 months. Shoulder, wrist, arm,
elbow and fingers were found to be the most commonly
affected regions among the weavers.
An anthropometric database (Table 3) was established
for hand dimensions of the weavers.
3.2. Phase 2
Based on ergonomics hand tool design principles, and
hand anthropometric dimensions of the weavers, proto-
types for weaving comb, knife and scissors were developed.
The details of design process are presented below.
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Table 1
Some personal details of the carpet weavers studied in three Iranian
provinces (n¼862)
Age (years) Mean (SD) 36 (14.8)
Min–max 15–82
Weight (kg) Mean (SD) 58.7 (11.5)
Min–max 28–100
Height (cm) Mean (SD) 159 (8.7)
Min–max 137–190
Weaving experience (years) Mean (SD) 21.2 (15.4)
Min–max 1–50
Daily working hours (h) Mean (SD) 7.5 (2.1)
Min–max 1–13
Table 2
Frequency of reported musculoskeletal symptoms in both dominant and
non-dominant upper extremities of the carpet weavers during the 12
months prior to the study (n¼862)
Upper limb regions No. (%)
Shoulders 590 (68.4)
Arms 351 (40.7)
Elbows 241 (28)
Forearms 220 (25.5)
Wrists 375 (43.5)
Hands 153 (17.8)
Fingers 271 (31.4)
M. Motamedzade et al. / International Journal of Industrial Ergonomics 37 (2007) 581–587 583
Weaving comb handle design: As shown in Fig. 1, a non-
slip texture has been used to improve grips by increasing
the friction between the hand and the handle. The tool
handle has been oriented in such a way that while working,
the hand and the forearm were aligned and no significant
deviation from neutral posture occurred. Fig. 2, a picture
taken during prototype design stage, shows the weaver’s
hand posture during working with weaving comb. To avoid
stress concentration on the palm, the end and the base part
of the handle had larger diameter and was extended out of
the closed hand.
Weaving comb handle length calculation: According to
Lewis and Narayan (1993), the length of handle was
calculated using hand breadth (palm) (Table 3) [[(P
5th
hand
breadth of males+P
50th
of hand breadth of males)+P
50th
hand breadth of females]/3]+15:
½½ð90 þ102Þþ93=3¼95 þ15 ¼110 mm.
Fifteen millimeters was added to the length of the handle
because the handle length must be longer than the widest
part of the weaver’s hand during carpet weaving for
preventing contact stress on the palm of hand.
Weaving comb handle diameter calculation: Weaving
comb can be classified as a power grip hand tool. In order
to calculate the diameter of the handle in the thickest part,
grip diameter (inner) was used (Table 3): [(P
5th
grip
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Table 3
Hand anthropometric dimensions of Iranian carpet weavers (in mm)
Dimensions Male (n¼224) Female (n¼638)
Percentiles SD Percentiles SD
5th 50th 95th 5th 50th 95th
Hand length 168 182 198 9 157 171 185 9
Palm length 80 98 112 11 77 92 103 9
Thumb length 43 52 62 6 42 50 58 5
Thumb breadth 19 22 26 2 17 20 23 3
Index length 63 72 80 5 62 68 76 5
Index breadth 18 20 23 3 17 19 21 3
Middle length 70 79 88 6 67 75 83 5
Middle breadth 18 20 23 2 16 18 21 2
Ring length 64 72 79 5 61 68 75 5
Little length 51 58 66 5 49 55 63 5
Little breadth 15 18 20 2 14 16 18 2
Hand thickness 34 44 54 6 26 34 48 8
Hand breadth (4 fins.) 75 84 100 8 67 76 88 6
Hand breadth (palm) 91 102 113 7 85 93 103 6
Index thickness 15 18 21 2 14 16 19 4
Hand length (grip) 97 110 125 10 89 100 115 10
Grip diameter (inner) 33 41 50 5 32 39 45 5
Grip diameter (outer) 88 99 108 7 79 90 99 6
Wrist thickness 37 42 50 4 34 39 47 4
Wrist breadth 53 60 73 6 50 57 68 6
Fig. 1. Weaving comb; Left: traditional design, Right: comb with new
ergonomic handle.
Fig. 2. Weaver’s hand posture during work with the weaving comb
prototype.
Fig. 3. Weaving knife; Top: knife with new ergonomic handle, Bottom:
traditional design.
M. Motamedzade et al. / International Journal of Industrial Ergonomics 37 (2007) 581–587584
diameter of males+P
50th
of grip diameter of males)+P
50th
grip diameter of females]/3.
½½ð33 þ41Þþ39=3¼38 mm.
The calculated values were applied for making proto-
type.
Weaving knife handle design: As shown in Fig. 3,
an appropriate non-slip texture was used to improve
grips. The guard on the sharp edge prevented slip of the
hand over the blade and resulted in safe operation.
The rounded end of the handle was extended out of the
closed hand that caused stress reduction on the palm. No
groove was provided to accommodate wide variations in
finger anthropometry of the users. Fig. 4 shows the
weaver’s hand posture during work with the new weaving
knife.
Weaving knife handle length and diameter calculations:
The same procedure as weaving comb handle design was
applied for weaving knife design. Weaving knife is
classified as a precision grip hand tool. Thus, the handle
diameter was reduced to 25 mm to make the prototype of
the weaving knife.
weaving knife handle length: 110 mm,
weaving knife handle diameter: 25 mm.
Weaving scissors handle design: As shown in Fig. 5,
an appropriate texture was used to prevent slip and
contact stress on the hand and fingers. The tool
handle was oriented such that during work the wrist
was kept in healthy posture and no significant deviation
from the neutral posture occurred. The rounded end
of the handle was extended out of the closed hand,
which caused stress reduction on the palm. Fig. 6 shows
the weaver’s hand posture during work with weaving
scissors.
The handle length of the scissors was determined to
be 110 mm (see weaving comb handle design). To obtain
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Fig. 5. Weaving scissors; Top: scissors with new ergonomic handles,
Bottom: traditional design.
Fig. 4. Weaver’s hand posture during work with weaving knife prototype.
Fig. 6. Weaver’s hand posture during work with the weaving scissors
prototype.
M. Motamedzade et al. / International Journal of Industrial Ergonomics 37 (2007) 581–587 585
a desired handle diameter for the scissors, three proto-
types with handle diameters of 10, 15 and 20 mm were
made and tested. As the weaving scissors were applied in
precision tasks, in accordance to NIOSH recommendation
(2004), 80 mm was considered for open grip span of the
scissors.
Prototype testing results: In 80% of cases (eight weavers),
the scores of usability tests were above 90 for all three
prototypes. According to the interpretation of
checklist score proposed by Dababneh et al. (2004), this
meant that the prototypes were not lacking any
highly important ergonomic design features. In 20% of
cases (two weavers), the scores ranged from 77 to 85 for the
three prototypes. All scores obtained for the old hand tools
were lower than 70. The Wilcoxon signed-rank test
revealed significant differences between the scores of the
old and the new designed tools. Based on the results of
statistical analyses, there was a significant preference
towards the comfort and applicability of the prototypes
(po0.01).
During the prototype testing, based on the participants’
suggestions, some modifications were undertaken in the
prototypes as follows:
The shape of comb handle was changed from round to
oval with 35 and 25 mm of diameter.
The shape of knife handle was changed from round to
oval with 15 and 20 mm of diameter. The handle length
was acceptable for the weavers.
The scissors with 15 mm of handle diameter were
preferred by the weavers. The designed handle
length and span were found to be acceptable for the
weavers.
4. Discussion
The questionnaire showed that symptoms from
the upper limbs were common among weavers. High
percent of weavers had experienced some kind of
symptoms from the upper limbs during the last 12 months
(Table 2). This is in agreement with the results of
the findings of the study of Choobineh et al.
(2004a). According to literature, these problems can be
attributable to hand tools design issues (Lewis and
Narayan, 1993;Kadefors et al., 1993;Armstrong et al.,
1982;Aghazadeh and Mital, 1987;Armstrong, 1986;
Sperling et al., 1993).
Similar to other hand tools, the purpose of the handle
usage in carpet weaving tools is to facilitate the transmis-
sion of force from the weaver’s musculoskeletal system to
the tool or the carpet she/he is weaving. To optimize force
transmission, it is necessary to optimize handle design
(Pheasant, 1999). Therefore, in this study the handle design
was considered the critical factor in safe, comfortable and
easy use of the carpet weaving hand tools.
Poor designed, traditional hand tools are commonly
used in carpet weaving operation. It seems that these
traditional hand tools greatly need redesigning. Any
improvement in the design of carpet weaving hand
tools may considerably improve health and safety of a
large number of weavers working in Iranian carpet
industry.
This study focused on redesigning three dominant types
of common hand tools in carpet weaving operation,
including weaving comb, knife and scissors. The results
of the usability test indicated that the ergonomic handles
were comfortable and applicable to the weavers. No
soreness was reported in the palm of hands by the
participants while working with the new tools. During
work with the prototypes, the wrist was in appropriate
posture. Generally, the results of the usability test showed
that the new designs were applicable and acceptable for the
weavers.
5. Conclusion
This study showed that upper limbs MSDs occurred
at a high rate among carpet weavers. From the usability
test, it could be concluded that, new hand tools caused
the concentration of contact stress on the palm of hand
to be eliminated. The designed handles were perceived
more comfortable than conventional ones. The new
ergonomically designed weaving hand tools were
found to be applicable and acceptable for the carpet
weavers. However, further study is needed to make
appropriate revisions to the ergonomically designed
tools based on quantitative measures of musculoskeletal
loading.
In this study, no attempt was made to measure the
effects of the new weaving hand tools on weavers’
performance. Further field trials will be needed to test
efficiency under real production conditions.
Acknowledgement
The authors gratefully acknowledge the support of
Center for Carpet Research, Iranian Ministry of Com-
merce.
Appendix A
Checklist used for ergonomic evaluation of carpet
weaving hand tools, including weaving knife, weaving
comb and weaving scissors, modified from Dababneh et al.
(2004)
Please respond to each item on the checklist by ‘‘Yes’’,
‘‘No’’ or ‘‘NA’’ (not applicable). Write the score in the
‘‘Score’’ column. Add the scores of all items to get the total
score of the usability test.
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ITEM ERGONOMIC FEATURE YES NA NO SCORE
1 Tool handle surface have a non-slip surface. +10 0
2 Tool handle surface is without sharp edges. +10 0
3 Tool handle is made of wood. +10 0
4 Tool handle surface is thermally insulated. +2 0
5 Tool handle surface is coated with soft material. +10 0
6 Tool handle length is 100-150mm. +10 0
7 For weaving knife and weaving comb:
Size of the handle cross section is not too small and not too
large and a minimum overlap between index finger and thumb
(25mm) is possible.
+8 0 0
8 For weaving knife and weaving comb:
Shape of handle cross section is oval.
+2 0 0
9 For weaving scissors :
The shape of handle cross section is circular.
+2 0 0
10 For weaving scissors:
Grip span is greater or equal to 50mm when fully closed and
less than or equal to 80mm when fully open.
+10 0 0
11 Angle of the handle is formed so that the work can be done
keeping a straight wrist.
+10 0
12 The tool weight is less than 2.3 Kg. +10 0
13 The tool can be used by either hand. +2 0
14 The tool can be used by the weaver's dominant hand. +10 0
15 The tool will allow two-handed operation during weaving. +4 0
16 The tool is color coded so it is easy to identify. +2 0
Total score of the tool (100 points possible)
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M. Motamedzade et al. / International Journal of Industrial Ergonomics 37 (2007) 581–587 587
... Hand tools are frequently used by workers in a vast number of industrial occupations [1][2][3]. Working with hand tools has been linked with several musculoskeletal risks [3,4], especially upper extremity cumulative trauma disorders (CTDs) in According to the literature, about half of the top 10 industries reporting musculoskeletal disorders including assemblers, construction workers, supervisors in sales, carpenters, and cashiers, are at risk of developing work-related musculoskeletal disorders (WMSDs) in the upper extremity through hand-stressing work or the use of improper hand tools [10]. The US Department of Labor, Bureau of Labor Statistics, (2013) showed that the incidence rate of occupational injuries related to upper extremities (shoulder, arm, wrist, and hand) was 32.5%. ...
... Hand tools are frequently used by workers in a vast number of industrial occupations [1][2][3]. Working with hand tools has been linked with several musculoskeletal risks [3,4], especially upper extremity cumulative trauma disorders (CTDs) in According to the literature, about half of the top 10 industries reporting musculoskeletal disorders including assemblers, construction workers, supervisors in sales, carpenters, and cashiers, are at risk of developing work-related musculoskeletal disorders (WMSDs) in the upper extremity through hand-stressing work or the use of improper hand tools [10]. The US Department of Labor, Bureau of Labor Statistics, (2013) showed that the incidence rate of occupational injuries related to upper extremities (shoulder, arm, wrist, and hand) was 32.5%. ...
Article
Nowadays, musculoskeletal disorders resulting from working with improper hand tools have been known as one of the major concerns in various industries. In the current study, an ergonomic nail removal device was proposed to evaluate the intervention for nail removal activity in the woodworking and carpentry industry. Eleven male workers, who were actively involved in nail removing activity, were asked to perform nailing activity by removing nails driven into the bottom and top of the door as the base points for painting the doors using both the nail removal device and the traditional plier. The Rapid Entire Body Assessment (REBA) and Strain Index (SI) techniques were used to characterize the level of risk. Moreover, nailing task duration and task repetition were measured as important criteria in manual works. According to the SI and REBA risk indices, the final scores for the designed device were estimated at 2 (low-risk level) and 1.5 (safe), respectively, while these values for the traditional pliers were 12 (high-risk level) and 15 (dangerous). Moreover, using the designed electric nail removal device led to a reduction in the repetition and duration of the task. Overall, the application of the proposed device in the nail removal tasks has shown risk indices below the critical thresholds in terms of correcting work posture and reducing strains imposed on workers' upper limbs.
... Values obtained from this present study were lower compared with some related studies done 40 41 by Mokdad , Taha and Nazaruddin and Motamedzade 42 et al , these differences could be as a result of population and ethnic differences, and the fact that whereas most of the jobs in the automotive industries in Nigeria are floor based. ...
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This study examined the relationship between hand anthropometry and hand dominance among selected Nigerians in the automotive industry. A cross-sectional, descriptive study was carried out on 45 male automotive workers between the ages of 30-49, in selected automotive workshops located in the city of Port Harcourt. Exclusion criteria were; history of upper limb injuries or disorders. The following parameters were measured from the upper limb; mid-arm circumference, arm length, forearm length, hand length and hand width. Handgrip strength was measured on right and left hands by using a standard adjustable digital hand grip dynamometer (CAMRY EH101), Zhongshan Camry Electronics Ltd, Shinqi, China. Paired t-test and Pearson's correlation were employed. A probability (p)<0.05 was taken to indicate level of statistical significance. Data analysis was carried out with Statistical Package of Social Sciences (SPSS) version 23.0. Dominant handgrip strength (43.18kgf) had a higher average value than non-dominant hand grip strength (36.00kgf). Mid-arm circumference mean was 25.29 ± 3.23cm. Arm and forearm length values were 31.41 ± 1.95cm and 27.51 ± 1.95cm respectively. Hand length and width values were 18.70 ± 1.19cm and 8.71 ± 0.63cm respectively, with hand index (46.60 ± 2.50). Positive correlations were observed between handgrip strength and anthropometric parameters such as arm length (R = 0.34, p = 0.02) and forearm length (R = 0.34, p = 0.02). The application of hand dominance and its anthropometry is essential in the design of occupational equipments especially in the automotive industry for better management and rehabilitation of hand-related injuries.
... As a result, gathering data on the anthropometry of hands and feet can be extremely beneficial in reducing musculoskeletal injuries to these organs and optimizing the design of related products [18] . In this regard, Motamedzade et al. investigated the anthropometric dimensions of hands in Iran in order to design hand tools for carpet weavers [20] . Heidari Moghadam et al. investigated the ten anthropometric dimensions of the hand and discovered that anthropometric dimensions are influenced by factors such as age, gender, and genetics [9] . ...
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Aim: Since the mismatch between the anthropometric dimensions of individuals and the dimensions of hand tools and shoes which leads to musculoskeletal disorders (MSDs), measuring data on anthropometric dimensions of hands and feet is essential for designing hand tools and shoes production. This study aimed to measure the anthropometric dimensions of hands and feet in different ages of men and women in Tabriz, Iran. Method and Materials: This is a descriptive-analytical study that was conducted in 2020 on 609 peoples living in Tabriz city in Iran. In this study, two and one dimensions of foot and hand were measured manually respectively. Descriptive statistics such as percentages, means, and standard deviation were calculated. Independent t-test and Cohen effect size were used to test the mean dimensions of hands and feet of subjects. Finding: Mean, standard deviation and 5th, 50th and 95th percentiles values were calculated in general and in terms of gender and educational level for individuals. In all the measured dimensions, men were generally larger than women, however; there were exceptions. The mean of the measured dimensions of hand foot size between men and women was different significantly. Conclusion: In this study, anthropometric data of hands and feet for people living in Tabriz were measured. The findings provided can be used to design hand tools and shoes productions.
... Furthermore, it is found that ergonomically designed handles have a significant effect on the flexor and extensor muscles of the forearm by reducing the muscle load in that region. These handles also showed an increased level of subjective reliability and usability (Motamedzade et al., 2007;Shimomura et al., 2016). It is important to incorporate the hand anthropometric data in designing the handle of hand tools, to obtain optimal outcomes in terms of usability and comfort (Kong and Kim, 2015). ...
Article
Teaching professionals regularly use the chalk board eraser or duster throughout their life which leads to several unnoticed musculoskeletal disorders. The purpose of this study was to provide an alternate design for the existing Indian model chalk board eraser, because current eraser design causes noticeable amount of biomechanical load on the wrist, hand and shoulder region when its frequency of usage was high and repetitive. Initially, pilot study was conducted through an online modified Nordic questionnaire among 60 college professors to identify the risky regions of the body due to the use of existing chalk board eraser. This was followed by an experimental trial using surface Electromyography Sensors (sEMG) in which the muscle behaviour was evaluated during the chalkboard erasing process employing three newly designed dusters and a traditional duster. The results revealed that Model A designed with a large palm rest to align the palm and the forearm had better usability and the musculoskeletal distress was reduced when compared with the traditional duster. Whereas Model C designed with slip guards to improve the gripping forces was found to have better performance rating after Model A. Model B provided with separate handle was found to be the worst performer when compared with the conventional duster. Results suggested that providing an improved palm rest and slip guards such as grooves reduces the musculoskeletal distress.
... La mano humana está funcionalmente especializada para la manipulación, y en términos de cognición, las herramientas generalmente se integran en el esquema corporal cuando se utilizan [11]. En muchas ocupaciones, las principales causas de la presencia de trastornos y enfermedades de trabajo, se encuentran relacionadas con el uso de herramientas manuales [12]. Existe evidencia de que las actividades musculares se reducen después de implementar cambios en el trabajo asociados con mejoras en el trasporte de materiales, evitando posturas con flexiones profundas, arreglando herramientas manuales y organizando mejor el trabajo [13]. ...
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En la actualidad los procesos de trabajo son altamente automatizados, sin embargo, a pesar de tantos avances en el área industrial, gran parte de las actividades se continúan realizando con el uso de herramientas manuales, es por esta razón que un diseño apropiado es decisivo para prevenir la presencia de trastornos músculo-esqueléticos. Por lo que este trabajo tiene el objetivo de determinar la fuerza de torque ejercida con cinco mangos de desarmador con diferentes diseños, así como el encontrar la existencia de diferencias significativas en la fuerza ejercida con cada uno. Para este trabajo, se tomó una muestra de 73 estudiantes, de los cuales 45 fueron hombres y 28 mujeres, utilizando el analizador digital de torque Mountz Torque Analyzer del modelo EZ-TorQ II 10i, en dónde se obtuvieron resultados de fuerza aplicada para los cinco mangos. Como resultados se obtuvo en el mango A una fuerza de 3.98 ± 1.54 Nm, en el mango B; 3.90 ± 1.55 Nm, en el mango C; 3.42 ± 1.25 Nm, el mango D; 3.40 ± 1.23 Nm y por último en el mango E; 3.51 ± 1.28 Nm. A través del Análisis de Varianza se encontró, que efectivamente existe una diferencia significativa en la aplicación de fuerza con el uso de estos diseños de mangos, encontrando que el diseño que optimiza la aplicación de fuerza es el mango A. Los resultados de esta investigación sirven como una guía para el diseño de mangos de herramientas manuales, se recomienda para futuros estudios, tomar en cuenta otro tipo de dimensiones antropométricas del miembro superior, así como ampliar la muestra y el rango de edades de los sujetos de estudio.
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Background and Objective: Hand anthropometric data can help us properly design hand tools for better efficiency and less fatigue in individuals. This study aimed to measure and analyze hand anthropometric data of Iranian farmers in order to determine the characteristics of farmers' hands separately for each ethnicity so that they can be used to design hand tools and working stations. This study measured 8 dimensions to design the appropriate hand tools in Iranian farmers. Materials and Methods: This study measured the hand dimensions of 600 farmers in four ethnicities of Lor, Kurd, Arab, and Fars in Iran. Moreover, it attempted to compare the data taken from the employees' hand dimensions in each ethnicity separately, as well as those in other countries to design hand tools appropriate for the corresponding country. Results: The results showed the mean length of hand (19.82±1.53), hand metacarpal width (9.47±1.59), hand width to thumb tip (11.81±1.33), and hand metacarpal thickness (2.78±0.29) were the highest in Kurd ethnicity. Moreover, the palm length (10.82±0.84) was the highest in Arab ethnicity. Furthermore, the index finger diameter (2.40±0.39) and hand circumference (28.71±1.51) obtained the greatest values in Fars ethnicity. The results of the comparison made between hand dimensions in Iran and those in other countries showed that the Iranian metacarpal hand width was larger than that in other countries, such as India, northern Nigeria, and Jordan. In addition, the hand thickness of Nigerian people was greater, compared to that in the Iranian population. Conclusion: These findings can help interior designers design appropriate hand tools that cause a reduction in ergonomic problems in domestic farmers.
Article
Work-related musculoskeletal disorders (WMSDs) are closely identified with common complaints in different workplaces. This study aimed to implement an intervention program through which ergonomic measures were dynamically localized in industry. An interventional study, including three basic layers, namely, training workshops, participatory ergonomics (PE), and workstation redesign was fulfilled in an Iranian steel manufacturing complex from 2017 to 2020. A steering committee (SC) was formed following several meetings held for clarification of the project to the management team. The SC members then attended four organized workshops managed by an ergonomics specialist. Afterwards, the basics of ergonomics were transferred to action groups. After developing ergonomic assessment tools, the ergonomic problems were prioritized and numerous positive changes were made by the action groups. The findings of the tailored checklists revealed a load of WMSDs risk factors. All the three layers of the program were implemented as initiated. Ergonomics training workshops were then held and significant differences were observed between the participants' pre/posttest mean scores in all workshops (p < 0.001). Moreover, PE measures were exercised at all levels of the organization inducing enthusiastic motivation of the workforce to consider ergonomic requirements in the workplace. Consequently, the workers' innovative ideas and the managerial support yielded diverse workstation redesigns due to a growth in either the workers' ergonomics awareness or participatory culture grounding. A multilayered ergonomic intervention was implemented in this study. In conclusion, a multifaceted long-term follow-up intervention program could be applied to enhance workers’ health status and to raise system productivity.
Article
Background: Hand anthropometry is useful for designing manual systems such as hand tools, controls, and gloves. There are limited published data on the hand dimensions of Iranian male and female adults. Objective: This study was undertaken to measure the hand anthropometric dimensions in Iranian adults to compare data between two genders and also with the corresponding data from other nationalities. Methods: A total of 34 dimensions of the right hand were measured in 217 male and 128 female adults using a digital caliper and tape. The mean, standard deviation, and the main percentiles are summarized in a table and the mean of each dimension is compared by independent t-tests between genders. Hand dimensions are compared between Iranian and other nationalities such as North Colombian, Korean, Turkish, Nigerian, Bangladeshi, Jordanian, and Vietnamese using the published data. Results: Females had significantly smaller hand dimensions than males in all dimensions ranged from 4.21%to 18.16%, with the largest differences in hand breadths. Compared with other nationalities, the Iranian male and female adults had wider (greater breadth and circumferences) hands with shorter fingers. Conclusions: The results showed significant differences of hand anthropometry between Iranian and other nationalities which should be included in the design and selection of hand tools for Iranian population.
Chapter
The ergonomic risk assessment of the postural attitude of the workers is essential for evaluating physical workload in the workplace, especially when they interact with workstation elements. Exposure to heavy physical work and repetitive actions are common among informal workers in handicraft work while interacting with non-ergonomic tools. Such working conditions, consequently, lead to the development of musculoskeletal disorders (MSDs). In this context, a study has been conducted on handcrafted Kalash polishers in brass metal handicraft production units located in northeast India, where most of the polishers in the polishing task use a traditional polishing tool, and their working postures are mostly constrained by the design of polishing tool. Therefore, the present study aims to determine the occurrence of MSDs and the ergonomic risk of working postures of Kalash polishers in brass metal handicraft production units. The study sample comprised of 40 polishers. Nordic Musculoskeletal Questionnaire (NMQ), Rapid Upper Limb Assessment (RULA) tool, non-invasive postural acquisition using cameras, virtual prototyping, digital human modeling, and simulation software were used. The results of this study revealed that 100% of polishers reported musculoskeletal discomfort in at least one body region during the past 12 months. The highest prevalence of MSDs was found particularly in the lower back (75%), followed by upper back (52.5%), elbows (50.0%), and hand/wrist (47.5%) regions. The mean severity of pain using the five-point rating scale indicated moderate to high pain in the lower back, upper back, and shoulder regions. Further, the simulation results indicated that the adopted working postures of polishers were at a very high-risk level with the existing polishing tool. Based on these findings, implications for further research include the design/redesign of the existing polishing tool based on ergonomic principles, which may improve working postures and reduce the risk of MSDs among this occupational group.
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The concept of androgynous or gender-neutral fashion is known for its distinctive attribute that blends both conventional masculine and feminine design characteristics. In the history of fashion, the notion of androgynous fashion has been evolving since the 1920s, although it was irregular at times. In the postmodern Western cultures, androgynous aesthetic in fashion is increasingly accepted, encouraging the multiplicity of gender expressions. With significant influencers of the generation identifying themselves as gender-neutral and speaking out on the topic, the concept of being gender fluid is catching a lot of attention recently in the international fashion industry. Androgynous fashion is an emergent trend, which reflects in fashion ramps with models showcasing silhouettes and design elements that breakdown gender stereotypes. With this in mind, the current research aims to study androgynous fashion from both conceptual and user-centric perspectives in the Indian context. Data were collected through primary and secondary sources. Relevant secondary data were gathered from various books, research papers and fashion publications to set the conceptual context of the research. Additionally, to gather primary information about the Indian LGBTQ consumers’ perception of androgynous fashion, a questionnaire was circulated amongst young Indian fashion consumers using convenience and snowball sampling methods. The results and analysis of the study reveal the aspirations behind the gender-neutral design genre. This study also brings out the emotional needs of the Indian LGBTQ community members, who are the primary consumers of androgynous aesthetic.
Article
Objective: Repetitive and forceful use of wrist and finger flexors is purported to be an occupational risk factor for carpal tunnel syndrome (CTS). While weaving carpet, wrist and finger flexors and extensors are used repetitively, with pinching movements and forced grasping. We aimed to investigate CTS frequency in hand-made carpet workers. Methods: Seventy women from carpet workshops in the city center and 30 healthy unemployed women were evaluated by clinical examination and electrophysiology. The relationship between CTS development and employment duration, and work produced per year were also investigated. Our study is cross-sectional. Results: CTS was present in 31 hands (22.1%) of workers and in four hands (6.7%) of the control group. The estimated relative risk of developing CTS was 3.3 times greater in carpet-workers than it was in controls. Considering all hands, we could not find any correlation between CTS development and employment duration (P=0.977), or with work produced per year (P=0.505); but these two were the prominent factors contributing to delayed median sensory latency (P=0.013, P=0.009, respectively). Conclusions: We could not find any correlation between CTS development and employment duration, or with work produced per year; but these two were the prominent factors contributing to delayed median sensory latency The results indicates that women working in the hand-made carpet industry have a higher risk of CTS development.
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In this paper, handles for two commonly used hand tools, the chisel and the off-set pliers, are designed using ergonomic principles. These were sized for both males and females falling in the 5th percentile, 50th percentile and 95th percentile groupings. The stresses developed in the ergonomically designed chisel handle while in use were analysed to verify the validity of the design. This chisel handle was then manufactured, and preliminary evaluation using electromyography was conducted. In these tests, the stresses exerted on the flexor and extensor muscles of the arm were measured and compared with those obtained during the use of a conventional handle. Under similar working conditions, results clearly showed that the ergonomically designed handle allows higher working efficiency than existing handles.
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In an interdisciplinary research project, a model, visualized as a cube, was developed for the classification and analysis of work with hand tools and for communication of different ways of solving problems related to manual handling. The dimensions of the cube are demands of force, precision and time. Each dimension is divided into three levels of low, moderate and high demands respectively. Preliminary limits are proposed for acceptable and non-acceptable use situations and for situations that have to be investigated further. Using a case study of plate shears as a starting point, various measures of improving the position in the cube are discussed. The hand tool, the workplace, the work organization as well as the user of the hand tool are included in the analysis.
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The authors present a case of a median nerve entrapment in a girl who was in the training of carpet weaving.
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Chronic tendon and nerve disorders of the upper extremity, such as tendinitis and carpal tunnel syndrome, are a common problem among persons who routinely perform hand-intensive work. This article summarizes the most commonly reported occupational risk factors: repetitiveness, forcefulness, certain postures, mechanical stresses, exposure to vibration, and exposure to low temperatures. It describes how to look for these factors and how to control them through the design of work equipment and procedures.
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Cumulative trauma disorders such as carpal tunnel syndrome and tenosynovitis can be caused, precipitated, or aggravated by repeated exertions with the hand. This paper describes a study in a poultry processing factory that proceeds from an analysis of health records to an analysis of work methods, postures and forces. Alternative work procedures and knife designs are recommended to reduce stressful work postures and forces.