• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.148-153
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• 2005

Computer dominated jobs and industrial automation have rapidly created work-related musculoskeletal disorders(WMSDs) and WMSDS are expanding to employee of other general industry. Specific risk factors associated with WMSDs include repetitive motion, heavy lifting, forceful exertion, contact stress, vibration awkward posture and rapid hand and wrist movement. The purpose of this paper is to analyze the effects of the neck muscle workload according to posture(joint angle) and load weight. Seven male students participated in this study. To analyze neck muscle workload was studied on electromyographic(EMG) activity for sternocleidomastoid and trapezius, was subjectively rated using a Borg's CR-10 scale. ANOVA showed that the CR-10 ratings and most EMG root-mean-square (RMS) value were statistically significant improvement according to posture(joint angle) and load weight. The results of this study indicate the joint angle and weight of neck muscle workload to provide safe working conditions. To reduce the large number and severity of WMSDs employees have been experiencing, we need to redesign the job in workplace to identify and control hazards that are reasonably likely to be causing or contributing to the WMSDs.

• Safety and Health at Work
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• v.10 no.3
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• pp.314-320
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• 2019

Background: Sitting posture may be related to risk factors, including inadequate weight-bearing support, particularly when maintained for long periods. Considering that body weight is loaded in a closed support system composed of the seat, backrest, floor and working surface, the aims of the present study were to describe the development of an ergonomic sitting workstation to continuously record weight-bearing at the seat, chair, backrest, work surface, and floor and to test its measurement properties: reproducibility, criterion-related validity, and sensitivity. Methods: Rigid bodies (1 to 30 kg) and participant weights were recorded to evaluate the workstation measurement properties. Results: Rigid body tests showed variation values less than 0.050 kg on reproducibility test and errors below 5% of measured value on criterion validity tests. Participant tests showed no statistically significant differences between repeated measures ($p{\geq}0.40$), errors were less than 2% of participant weights an sensitivity presented statistically significant changes (p = 0.007). Conclusion: The sitting workstation proposed showed to be reliable, valid and sensitive for use in future ergonomic studies to evaluate the sitting posture.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.195-201
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• 2020

A forest operation is considered as one of the riskiest environments for the development of musculoskeletal disorders because operators are exposed to harmful environmental conditions such as rough terrain, inclement weather, and poor working postures. In weed and kudzu removal operations, manual application is still common in Korea. In this study, we evaluated the ergonomic conditions of weed and kudzu removal in regeneration forests and the associated risk of musculoskeletal disorders. The risk of musculoskeletal disorders was evaluated using the Ovako Working Posture Analysis System and postural risk index. Postural risk was significantly higher for kudzu compared with weed removal operations. This suggests that kudzu removal operations must be improved to decrease postural risk.

• Journal of environmental and Sanitary engineering
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• v.20 no.4 s.58
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• pp.59-68
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• 2005

This study was designed to provide basic data on preventive plans by affecting factors that have analysed on musculoskeletal diseases. The survey were conducted from July 1 to 30, 2004 among 600 hair dressers working in Seoul and Gwangju using self-administration questionnaire. The results of this study are summarized as follows: The pain experience rate of musculoskeletal diseases. in the last one year was $55.2\%,\;35.7\%$ of respondents answered they had pain on shoulders, $30.6\%$ had pain on legs and feet, $28.9\%$ had pain on waist, $26.8\%$ had hands, fingers and wrist, $22.3\%$ had pain on necks and $17.6\%$ had pain arms and elbows more than disease on necks, shoulders, arms and elbows, hands, fingers and wrists, waist, shoulders legs and feet. The prevalence rate of the last week was $40.3\%$. The prevalence rate in each body parts of the last week was $23.3\%$ on legs and feet, $21.2\%$ on shoulders, $20.8\%$ on waist, $14.9\%$ on hands, fingers and wrists, $14.4\%$ on necks, $9.3\%$ on arms. Based on the results above, working posture, job stress and physical burden from task are highly related with pain. In order to prevent musculoskeletal disease of hairdressers, working posture shall be improved and leisure opportunities to relieve stress, and health management education shall be provided.

• Journal of Preventive Medicine and Public Health
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• v.26 no.1 s.41
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• pp.37-48
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• 1993

This study was conducted to investigate the prevalence rate of low back pain during past one year and its risk factors. The data were collected from 1,384 manufacturing factory workers from March 1, 1992 to August 30, 1992. The results obtained were as follows: 1. The one year prevalence rate of low back pain by manufacturing company was 38.4% in textile manufacturing, 35.2% in concrete reenforcement, 31.0% in cigarette and 26.1% in metal part(P<0.01). 2. In textile manufacturing, age groups with high prevalence rate of low back pain were 30's(36.8%) and 40's(36.4%) (P<0.05), and the one year prevelence rates of low back pain by marital state were 34.9% in married workers and 28.5% in unmarried(P=0.0511). 3. The one year prevelence rates of low back pain by job part are 35.0% in labor workers and 26.1% in clerical(P<0.05), and by work hour per day it was 34.9% in 9 or more and 28.9% in 8 or less(P<0.05). 4. The highest group of low back pain by work posture was 43.5% in 'lifting and transfering materials', and it by fitness of chair was 56.0% in uncomfortable one, and by height of working board was 33.6% in low working one. 5. In logistic regression analysis, significant determinants with low back pain were marital state(p<0.05), work hour per day(P<0.05), height of working board(P<0.01), and work posture(P<0.01).

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.55-64
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• 2010

This study tried to focus on nontraditional job that has not been studied in terms of the subjects associated with MSDs(Musculoskeletal Disorders). Specifically, dental procedure was the job to be analyzed in this study. An alternative method as well as a traditional method for viewing teeth while performing simulated dental procedures. Four graduated students did both methods(direct view and indirect view) as the subjects in this study. The method based on indirect view used a video camera and monitor to view the teeth. The experiment was conducted five times for each subject. The major findings in this study were as follows; 1) Job speed was increased with the repetitions for both methods, 2) Difference of Neck flexion between direct and indirect methods was statistically siginificant(Neck flexion for indirect method was dramatically decreased), 3) Difference of job speed between direct and indirect methods was statistically significant(Job speed for direct method was faster than that of indirect method), 4) Difference of error rate between direct and indirect methods was statistically significant(error rate for direct method was lower than that of indirect method), 5) Even though indirect method did not provide better performance in terms of job speed and error rate yet, it seemed to need a trade-off between two methods in the future since indirect method provided better working postures than that of direct method.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.525-534
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• 2011

This paper describes the current status of musculoskeletal disorders(MSDs) and its ergonomic risk factors, including the preventive intervention in terms of the working conditions and health promotion among agricultural workers. Korean agricultural workers have been exposed to the poor working condition. They have suffered from a variety of work-related injury and diseases more than the general population or the other occupational group. MSDs are one of the most prevalent problems threatening the agricultural worker's health and quality of life. Low back pain, osteoarthritis of hip and knee joint and carpal tunnel syndrome are well known MSDs that was found easily and frequently among agricultural workers. MSDs are worsened by poor ergonomic working conditions such as heavy weight lifting, repetitive movement and awkward posture which involves squatting with long sitting work on the ground, long working hours and heavy workload which are inherent in the greater part of agricultural works. Even though Korean agricultural workers are very weak population in terms of occupational safety and health, no many studies were conducted in the past and no many social and institutional supports were provided sufficiently. We need more interests and efforts in agricultural fields to improve its working condition and to promote health status of agricultural workers.

• Journal of the Ergonomics Society of Korea
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• v.25 no.2
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• pp.51-62
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• 2006

In assessing risks related to working posture, pictures of postures are taken from various directions, which can be a source of observation error. Joint postures of the neck, lower back, knee, shoulder, and elbow were taken from 7 different viewing angles and 19 observers estimated joint angles by observing the pictures in 2-dimensional display. The joint angles were also measured using an optoelectronic motion measurement system. The estimation error increased as the viewing angle varies from the right side of the human body, but the patterns differ according to which joint angles were being observed. Guidelines to increase the validity of observation of joint angles were presented based on the results. In general, it is recommended to maintain the viewing angle within 20 degrees from the right side of the human body, while different ranges of viewing angle are recommended for each joint angle.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.90-94
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• 1997

Many workers like welders are working in squat sitting postures with te object on the ground for an entire work shift. It is suspected that such prolonged squat sitting without any supporting stool would gradually cause musculoskeletal injuries to workers. This study is to quantitatively evaluate the physical stress caused by the prolonged squat sitting and to recommend a safe work/rest schedule for the task with squat sitting posture based on the lab experiment. In this study, 8 healthy student subjects participated in the experiment. They maintained a squat sitting posture for 16 minutes with 4 different stool height conditions: no stool, 10cm hight, 15cm height, 20cm height. Every 2 minutes, the discomfort was subjectively assessed using the magnitude estimation method for the whole body, lower back, upper leg and lower leg. Based on discomfort rating, we found that 10cm height stool relieved the workload most. Discomfort rating results also indicated that 20cm height stool showed the heghest workload, and that there was no difference in workload between 15cm height and no stool. We recommend to provide the workers with 10cm height stool for prolonged squat sitting tasks.

• Proceedings of the Safety Management and Science Conference
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• 2001.11a
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• pp.139-143
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• 2001

Work-related injurieshave become the issue in the twentieth century. Musculoskeletal disorders are the most common work-related injuriesand the most frequent from of work-related i11-health (more than 50％ of total work-related injuries (BLS 1990)). The workers at copy shops have complained of pain in their back, legs, and shoulders. Most of them work for more than 8 hours a day. They have claimed that their pains were associated with repetitive and continuous work over a long term. The purpose of this research is to suggest an ergonomically comfortable redesign of the copy machine. This study was performed by conducting a survey of copy shop workers who have complained of job-related physical pain, and analyzing their working postures. The copy machine was ergonomically modified to reduce the workers' pain. The VIS10N 3000 software was used to analyze the posture. The analysis showed significant difference in the ranges of back and neck motion (p<0.05).