• Journal of the Ergonomics Society of Korea
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• 제33권6호
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• pp.553-563
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• 2014

Objective: The purpose of this study was to evaluate the effect of gender (male, female) and grip spans (45, 50, 60, 70, 80mm) on total grip strength, resultant force, finger force and subjective discomfort rating. Background: In order to prevent musculoskeletal disorders, studies of hand tools need to be preceded based on grip strength, finger force, and subjective discomfort rating. However, experimental apparatus using tools such as pliers that reflect the actual work place was almost non-existent. Method: Fifty-Two (26 males and 26 females) participants were recruited from the student population. In this study, a pair of revised pliers, which can change grip span from 45 to 80mm was applied to estimate total grip strength, resultant force and individual finger forces. All participants were asked to exert a maximum grip force with three repetitions, and to report the subjective discomfort rating for five grip spans of pliers (45, 50, 60, 70, 80mm). Results: There were significant differences of total grip strength, resultant force, individual finger forces and subjective discomfort rating according to grip span. The lowest total grip strength was obtained from the grip span of 80mm for both genders. For resultant force, the highest resultant force was exerted at grip spans of 50, 60 and 70mm for females and 50 and 60mm for males. The lowest subjective discomfort rating was observed in the 50mm for both genders. Conclusion: Based on the result, 50mm and 60mm grip spans which provide the highest force and lowest discomfort rating might be recommendable for the male and female pliers users. Application: The findings of this study can provide guidelines on designing a hand tool to help to reduce hand-related musculoskeletal disorders and obtain better performance.

• Journal of the Ergonomics Society of Korea
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• 제33권6호
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• pp.477-486
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• 2014

Objective:This study aims to devise industrial injury prevention measures by analyzing industrial injury characteristics including the status of industrial injuries, source of industrial injury and accident type in order to prevent aging workers' industrial injuries that account for more than half in the workplaces in agriculture. Background: Continuous migration from farm to city takes place among young people in rural areas in Korea, a traditionally agricultural country due to rapid industrialization and economic development. The aging rate in rural areas in 2013 was 37.3%, about three times higher than the total aging rate of 12.2% in Korea. According to industrial injury statistics of the Ministry of Employment and Labor, the number of industrial injuries in agriculture shows an uptrend and the industrial injuries of aging workers account for more than 50% each year. Method: Of the 2,970 industrial injury cases occurred in the workplaces in agriculture for five years during 2008 and 2012 offered by a national agency related to health and safety, this study analyzed 1,767 industrial injury cases of aging workers. Results: As a result of an analysis on aging workers' industrial injuries by company size in agriculture, 89.8% of the total number of industrial injuries were analyzed to occur in small scale company. According to aging workers' industrial injuries by source of industrial injury and accident type, the outdoor floor and a fall were analyzed to be the highest at 16.5% and 26.1%, respectively. Conclusion: This study analyzed aging workers' industrial injuries by company size, age, job duration, accident severity, gender, nationality, the source of industrial injury and accident type in order to identify industrial injury characteristics in agriculture. Application: The identification of industrial injury characteristics of aging workers in agriculture is judged to be helpful to devising effective measures to prevent industrial injuries.

• Journal of Biosystems Engineering
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• 제35권3호
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• pp.206-213
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• 2010

The purpose of this study is to analyze musculoskeletal injuries in combine harvesting operation using a digital human model. In order to analyze problems in combine harvesting operation, the operations were broken into 5 work processes and then we preformed ergonomic and biomechanical analyses such as RULA test, Comfort Assessment and joint kinetic analysis for the each process. As a result, there was a clear need to change the combine operating environment, as the RULA score ranged from 4 to 7. In addition, we could find two major musculoskeletal injury factors which are the standing posture with upperbody forward tilting and inappropriate location of operating levers.

• Journal of Agricultural Extension & Community Development
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• 제19권4호
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• pp.1021-1039
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• 2012

Based on the ergonomic evaluation of workers in the domestic traditional Korean sweet manufacturer, one of the small scale agricultural product manufacturers, the purpose of this study is on estimating the specific works and muscles that have possibility of musculoskeletal disorder through an EMG experiment for quantitative evaluation. The method followed in an order: works that have musculoskeletal disorder risk were extracted through ergonomic assessment tools, RULA and REBA, and then EMG experiment on the postures was carried out with six healthy adult male patients. As an ergonomic evaluation result, work posture during the drying process had the greatest musculoskeletal disorder risk, and EMG activity in the cleansing work posture scored the highest among the drying, cleansing, and coating work postures. In particular in the drying work, relatively high EMG activities were shown in the two muscles in the lower body: biceps femoris muscle, and gastrocnemius, than any other muscles. Therefore, during the traditional Korean sweet workplace design in future, the workplace requires a posture that deeply bow wrist for a long time should be avoided.

• Safety and Health at Work
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• 제12권4호
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• pp.432-438
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• 2021

Background: We aimed to investigate the prevalence of low back pain (LBP) and its associated agricultural work-related, biomechanical factors among this population. Methods: We analyzed initial survey data from the Safety for Agricultural Injury of Farmers cohort study involving adult farmers in Jeju Island. The prevalence of LBP was calculated with associated factors. Results: In total, 1,209 participants were included in the analysis. The overall prevalence of LBP was 23.7%. Significant associations for LBP were the type of farming activity, length of farming career, prior agricultural injury within 1 year, and stress levels. Multivariate logistic regression analysis revealed three biomechanical factors significantly related to LBP: repetitive use of particular body parts; the inappropriate posture of the lower back and neck. Conclusions: Some occupational, and biomechanical risk factors contribute to LBP. Therefore, postural education, injury prevention education, and psychological support will be needed to prevent LBP.

• Journal of the Ergonomics Society of Korea
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• 제36권5호
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• pp.589-599
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• 2017

Objective: The objective of this study was to measure the upper-limb motions and postures of grapes-harvesting tasks using electrical goniometers and analyze the upper-limb motions in a kinematic way to assess the risk of musculoskeletal disorders. Background: Grapes farmers are exposed to various risk factors of musculoskeletal disorders (MSDs) such as repetitive upper-limb motions, non-neutral postures, and manual handling of heavy items. The farmers have to use scissors repetitively while harvesting grapes with their being arms elevated over the shoulder height, which presumed to increase the physical workload. It has been reported that the grapes farmers feel the harvesting task as the one of the hardest work in cultivating grapes. We tried measure the wrist and elbow angles while the farmers were carrying out harvesting tasks to understand how much workload the work impose on the farmers, which can be helpful in making interventions of preventing musculosksletal disorders among grapes farmers. Method: We measured joint angles at the right wrist and elbow with a wireless measuring system with two electrical goniometers from five grape farmers. The grapes-harvesting task was classified into 6 different subtasks: 1) searching, 2) picking, 3) cleaning, 4) carrying, 6) storing, and 7) miscellaneous tasks. The subtasks were compared by mean angles, 10%, 50%, and 90% APDF values of wrist flexion/extension, ulnar/radial deviation, and elbow flexion. Results: The Kruskal-Wallis tests showed that the 10th percentiles of APDF of ulnar/radial deviation and flexion/extension of the wrist significantly differs among subtasks (p<0.05). It was found that the farmers assumed more deviated wrist postures in the ulnar direction when they picking and adjusting the grapes. The use of scissors seemed to force the farmers to severely bend their wrist in the directions of ulnar deviation and flexion. The grapes-harvesting task showed similar wrist postures and motion with poultry deboning and milking tasks. Conclusion: The grapes harvesting tasks make the farmers take ulnar deviated and extended postures in the wrist. The use of scissors makes them take more severely deviated postures in the wrist. Safety guidelines including use of ergonomic scissors can be provided to the farmers to improve their work conditions. Application: The results of this study can be used as a basic data for the development of safety guidelines for agricultural work.

• Journal of the Ergonomics Society of Korea
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• 제35권5호
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• pp.361-370
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• 2016

Objective:The aim of this study is to evaluate contributions of individual finger forces associated with various levels of submaximal voluntary contraction tasks. Background: Although many researches for individual finger force have been conducted, most of the studies mainly focus on the maximal voluntary contraction. However, Information concerning individual finger forces during submaximal voluntary contraction is also very important for developing biomechanical models and for designing hand tools, work equipment, hand prostheses and robotic hands. Due to these reasons, studies on the contribution of individual finger force in submaximal grip force exertions should be fully considered. Method: A total of 60 healthy adults without any musculoskeletal disorders in the upper arms participated in this study. The young group (mean: 23.7 yrs) consisted of 30 healthy adults (15 males and 15 females), and the elderly group (mean: 75.2 yrs) was also composed of 30 participants (15 males and 15 females). A multi-Finger Force Measurement (MFFM) System developed by Kim and Kong (2008) was applied in order to measure total grip strength and individual finger forces. The participants were asked to exert a grip force attempting to minimize the difference between the target force and their exerted force for eight different target forces (5, 15, 25, 35, 45, 55, 65, and 75% MVCs). These target forces based on the maximum voluntary contraction, which were obtained from each participant, were randomly assigned in this study. Results: The contributions of middle and ring fingers to the total grip force represented an increasing trend as the target force level increased. On the other hand, the contributions of index and little fingers showed a decreasing trend as the target force level increased. In particular, Index finger exerted the largest contribution to the total grip force, followed by middle, ring and little fingers in the case of the smallest target force level (5% MVC), whereas middle finger showed the largest contribution, followed by ring, index and little fingers at the largest target force levels (65 and 75% MVCs). Conclusion: Each individual finger showed a different contribution pattern to the grip force exertion. As the target force level increase from 5 to 75% MVC, the contributions of middle and ring fingers showed an increasing trend, whereas the contributions of index and little fingers represented a decreasing trend in this study. Application: The results of this study can be useful information when designing robotic hands, hand tools and work equipment. Such information would be also useful when abnormal hand functions are evaluated.