• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.41-47
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• 2009

The purpose of this study, during the lifting task was researching the difference and a relationship between the ground reaction force and the grip strength by change of position. After grip strength has measured in symmetry position and asymmetry position at 45cm and 75cm of height of hand, ground reaction force was measured by same attitude lifting wooden box. We analyzed the difference of grip strength and ground reaction force in each position change. The results of grip strength, the grip strength of both hand were significant difference that in study subject symmetry and asymmetry position (p<0.01). The results of symmetry lifting task, the study subjects was significant difference of the ground reaction force difference by height (p<0.05). Asymmetry lifting task was significant difference of ground reaction force difference by direction of rotation was changed (p<0.01). The result of it will rotate with non-dominant hand side of lifting tasks from height 75cm where it easily maintains a balance possibility and decreasing the load of the hand. Therefore, from the workshop in the work people, it will be between the height 75cm and non-dominant hand side of trunk rotatory direction in the lifting tasks. Future study is necessary researched about the change of grip strength when the height of the hand is higher, and the difference of the ground reaction force when the change of weight.

• Journal of the Ergonomics Society of Korea
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• v.24 no.4
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• pp.15-21
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• 2005

Use of a glove made of materials with a low elasticity decreases the performance of the hand such as agility, dexterity, range of motion, and grip strength. The present study examined if the adverse effects of a low-elastic glove can be reduced by a design which accommodates the changes of hand surface lengths by hand motion. Two glove designs which provide patches of elastic cloth and pleats at the finger joints and knuckle were developed by considering the hand surface length changes, and then compared with two conditions(bare hand and conventional glove design that does not consider the dynamic characteristics of the hand dimensions) in terms of completion time in peg board insertion task, maximum grip strength, discomfort in hand motion, discomfort in force exertion, and overall discomfort by 24 right-handed participants. The test results confirmed that wearing of a glove significantly reduced the agility and grip strength capability of the hand and indicated that the novel designs were effective to lessen the performance decreases compared to the conventional design. Also, of the glove designs, the pleat glove design was found most preferred for both better hand performance and less subjective discomfort.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.1
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• pp.1-7
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• 2013

This study is aimed to investigate the association between anaerobic-aerobic exercise intensity and hand steadiness. Hand steadiness is the decisive contributor to affecting the job performance just as in the rifle shooting and archery in sports and the microscope-related jobs requiring hand steadiness in industries. In anaerobic exercise condition hand steadiness is measured through hand steadiness tester having 9 different diameter holes after each subject exerts 25%, 50%, 75%, and 100% of maximum back strength. In aerobic exercise occasion it is evaluated at each time heart rate reaches 115%, 130%, and 145% of reference heart rate measured in no task condition after they do jumping jack. The results indicate that an increased intensity in both types of exercise reduces hand steadiness, but hand steadiness at 25% of maximum back strength and 115% of reference heart rate is rather greater than at no exercise. Just as the relation between cognitive stress and job performance has upside-down U form, so does the association of physical loading to hand steadiness, which means that a little exercise tends to improve hand steadiness in comparison with no exercise.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.2
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• pp.23-35
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• 2013

Purpose : We intend to make the study date for an effect of therapy by comparing the functional level both before and after conducting handwriting training and strength training as a part of treatment to improve muscle strength and function of the patient's non-dominant hand. Method : 8 subjects in writing training group conducted hand writing training 30 minutes at once and three times a week for 4 weeks in total 12 times, and 8 subjects in muscle training group conducted muscle training program of putty and Rolyan ergonomic hand exerciser for 15 minutes respectively in sum up 30 minutes at once and three times a week for 4 weeks in total 12 times. 8 subjects in control group are not applied any training for 4 weeks. Results : It was much more effective in handwriting training than muscle strength training by Grooved pegboard because this study showed the speed decrease from 67.11 to 58.26 seconds in handwriting compared with muscle strength training which showed 5.22 seconds decrease from 67.54 to 62.32(P<.05). It showed about 1.34 muscle strength improvement from 6.60 to 7.94 in handwriting training and 0.92 improvement of muscle strength from 7.04 to 7.96 in muscle strength training by 3-jaw chuck pinch, so handwriting training was more effective(P<.05). It showed 11.58 seconds decrease in handwriting training from 26.62 to 18.01 seconds and 10.93 seconds decrease from 27.43 to 16.50 seconds in muscle strength training, so it was significantly shortened both in handwriting and muscle strength training(P<.05). Conclusion : Dexterity, muscle strength, and handwriting ability of non-dominant hand could improve both the handwriting training and the muscle strength training.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.17 no.1
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• pp.24-28
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• 2011

Background: The purpose of this study is to make a grip strength checker to make people measure their grip strength easily, based on standardized grip strength checker chart. Method: In this study, we measured right hand grip strength of 80 women residents of Deajeon (women in their 30s to 60s, 20 in each) 2 times per day for 5days in same conditions from 20th of November 2010 to 24th of November. it was measured by Jamar Hydraculic Hand Dynamometer made lately to compare with the current measuring equipment. No matter how big their hands are, their hands were fixed at second level. Measured as they sit on a chair and let their shoulders gathered and not be rotated, let their arms be 90 degree, wrist and forearm be at the middle for the first time, and took another after they took a rest, and measured the average of the two. Result: There was not a meaningful difference between the current measuring equipment and the equipment made lately (p>.05). Conclusion: It is thought that the equipment made lately can be believed. In addition, we want people to realize their own grip strength easily by this study.

• Journal of Bone Metabolism
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• v.25 no.4
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• pp.243-249
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• 2018

Background: The aim of this study was to determine the accuracy and error range of hand grip strength measurement using various methods. Methods: Methods used for measurement of hand grip strength in 34 epidemiologic studies on sarcopenia were analyzed. Maximum grip strength was measured in a sitting position with the elbow flexed at 90 degrees, the shoulder in 0 degrees flexion, and the wrist in neutral position (0 degrees). Maximum grip strength in standing position was measured with the shoulder in 180 degrees flexion, the elbow fully extended, and the wrist in neutral position (0 degrees). Three measurements were taken on each side at 30 sec intervals. The uncertainty of measurement was calculated. Results: The combined uncertainty in sitting position on the right and left sides was 1.14% and 0.38%, respectively, and the combined uncertainty in standing position on the right and left sides was 0.35 and 1.20, respectively. The expanded uncertainty in sitting position on the right and left sides was 2.28 and 0.79, respectively, and the expanded uncertainty in standing position on the right and left sides was 0.71 and 2.41, respectively (k=2). Conclusions: Uncertainty of hand grip strength measurement was identified in this study, and a significant difference was observed between measurement. For more precise diagnosis of sarcopenia, dynamometers need to be corrected to overcome uncertainty.

• Journal of the Ergonomics Society of Korea
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• v.26 no.3
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• pp.59-65
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• 2007

In this study, six grip spans (45mm-65mm) were tested to evaluate the effects of handle grip span and user's hand size on maximum grip strength, individual finger force, and subjective ratings of comfort using a digital dynamometer with individual force sensors. Forty-six males were assigned into three hand size groups according to their hand lengths. Results showed that overall 55mm and 50mm grip spans were the most comfortable sizes and associated with the highest grip strength in the maximum grip force exertions, whereas 65mm grip span was rated as the least comfortable size as well as the lowest grip strength. In the interaction effect of grip span and hand size, small and middle hand sized participants rated the best preference and the least preference grip spans differently with large hand sized participants. With respect to the analysis of individual finger force, the middle finger force was the strongest and the highest contribution to the total finger force, followed by ring, index and little fingers. In addition, it was noted that each finger had a different optimal grip span for exerting maximum force resulting in a bowed contoured shaped handle for two-handle hand tools. Thus, the grip spans for two-handle hand tools might be designed according to the users' hand and finger anthropometrics to maximize performance and subjective perception of comfort.

• Journal of the Ergonomics Society of Korea
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• v.29 no.5
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• pp.715-725
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• 2010

Many researches for grip strengths, using diverse ways such as subject, equipment, posture, method, has been conducted to investigate the differences of grip performance of dominant hand and non-dominant hand. It is hard to conclude, however, with one single or simple answer for this question based on researches due to various findings. Although 'the 10% rule' which is the dominant hand may produces a 10% greater grip strength than the non-dominant hand was often mentioned for this issue, there is still lack of supports for utilizing to general cases. This manuscript provides an overall review on the 53 research papers which were measured grip strengths of dominant as well as non-dominant hand in various conditions. According to this review study, many research findings reported that overall the grip strength differences between dominant and non-dominant hands were 6~10%, regardless of gender and age, followed by 0~5%, 11~15%, and over 16%. More detail information for grip strengths in both hands for gender and age groups were also presented in this study.

• The Journal of Korean Physical Therapy
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• v.23 no.6
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• pp.43-47
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• 2011

Purpose: The aim of this preliminary study was to use hand function tests to Hand dexterity levels provided by the type of compression garment and compression bandages in asymptomatic subjects and to collect baseline data for the comparison of hand functions in the patients with chronic arm lymphedema. Methods: The subjects of this study were 32 healthy volunteer female with a mean age of 45.8 years. Grip strength and hand functions were tested in three conditions-no compression, compression garment, and compression bandages-using the nine-hole peg test (NHPT), the box and block test (B&BT), Minnesota Manual Dexterity test (MMDT), and the hand-held Jamar dynamometer. Results: The grip strength was significantly low in the bandage condition (p<0.05). The performance in both compression groups (i.e., bandage and compression garment) decreased as the thickness of the compression material increased (p<0.05). Conclusion: The findings of this study suggest that grip strength and hand function scores are influenced by the characteristics of the compression applied. Future study is needed to determine the level of hand function between patients with chronic arm lymphedema and healthy individuals.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.511-516
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• 2013

Objective: The objective of this study is designing an optimal hand tool through maximum grip force study accordance to the hand grip span. Background: In order to prevent musculoskeletal diseases, studies on hand tool design are proceeding based on grip strength, finger force, and contribution of individual finger force on total grip strength. However, experimental apparatus using a tool that is actually used in work place was almost non-existent. Method: 19 males were participated in an experiment. Using the load cell inserted real plier, finger force, grip strength, and subjective discomfort rate of both hands (dominant and non-dominant) were measured in 5 different hand grip span(45mm, 50mm, 60mm, 70mm, and 80mm). Results: There was significant difference(p<0.001) of total grip strength, individual finger force and subjective discomfort rating according to various hand grip span(45, 50, 60, 70, and 80mm). Also, statistically significant different(p<0.001) was shown between the dominant hand and non-dominant hand. In addition, individual finger force in maximum grip was in order of middle finger, ring finger, index finger, and little finger. Conclusion: Optimal grip span of pliers that exerting maximum grip strength is 50~60mm. Application: This finding is expected to be used for designing proper pliers.