• 대한인간공학회지
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• 제32권4호
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• pp.297-301
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• 2013

Objective: The purpose of this study is to review the hazards of whole body vibration(WBV) and prevent human injuries due to WBV. Background: Vibrations that shake the whole body in vehicles and vessels is WBV. Vibration at a specific frequency, and intensity in the human body can act as a hazard. But, it has not yet done enough research about effects of WBV. Method: We analyzed and reviewed occupational or ergonomic papers published past 30 years. Results: Exposure to whole body vibration can cause permanent physical injury or damage of the nervous system. In addition, it may cause problem in the cardiovascular system, digestive system, musculoskeletal system, endocrine system, reproductive system, and psychological system. The effect of vibration depends on its acceleration, duration, frequency, and direction. Conclusion: WBV-exposed human body experience a high risk of some illnesses such as lumbar spinal disorders. Some workers(bus drivers, truck drivers and heavy equipment operators) are the high risk population exposed to WBV. Application: The results of this study might help to judge and prevent occupational disease caused by WBV.

• 농촌지도와개발
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• 제19권4호
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• pp.1021-1039
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• 2012

본 연구의 목적은 소규모 농산물 가공공장 중 하나인 한과작업장의 작업자들을 대상으로 인간공학적 평가를 실시하고, 이를 바탕으로 정량적 평가를 위해 실내 근전도 실험을 하여 어떤 작업에서 어떤 근육에 근골격계질환 가능성이 있는지 평가하는데 있다. 연구방법은 인간공학적 평가도구인 RULA 및 REBA를 이용하여 근골격계질환 위험 작업을 추출하고, 신체건강한 성인 남성 6명을 대상으로 근전도 실험을 하였다. 인간공학적 평가 결과 건조작업이 근골격계질환 위험도가 가장 높았으며, 건조 작업자세, 수세 작업자세, 고물 묻히는 작업자세 중 수세 작업자세가 근활성도가 가장 높았다. 특히, 건조작업에서 하지근육인 대퇴이두근과 비복근이 다른 근육들에 비해 상대적으로 근활성도가 높았다. 따라서 추후에 한과작업장 설계시 허리를 깊게 숙인 채 장시간 작업하는 자세가 없도록 해야 한다.

• 대한인간공학회지
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• 제25권2호
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• pp.119-124
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• 2006

The present study evaluated the accuracy of MSD-related work criterion of Korea Ministry of Labor by using ergonomic workload evaluation methods. 1,948 manufacturing works in automobile industry were divided into 1,286 MSD-related risky works and 662 risk-free ones by using RULA, ANSI Z-365 and perceived discomfort evaluation. Then, the two types of works were evaluated by Labor Ministry work criterion to analyze the classification accuracy of the work criterion. The work criterion of Korea Labor Ministry had low hit and false alarm ratio(20 and 11%) and high miss and correct rejection ratio(80 and 89%), and the odd ratios of hit and correct rejection were 0.2 and 8.3, respectively. It can be concluded that the work criterion of Korea Labor Ministry is a conservative evaluation method which tends to evaluate a target work as risk-free.

• 대한인간공학회지
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• 제30권5호
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• pp.637-644
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• 2011

Objective & Background: When applying various evaluation tools that analyze work posture risk through observation, accurate measurement of body flexion angle is very important. Method: This study investigated differences and appropriateness of 5 different existing reference points commonly used in the analysis of the work posture. Twenty five ergonomist and trained professionals were participated in this study. A Same flexion angle was utilized for the evaluation of risk assessment of musculoskeletal disorders using five different reference points to investigate the degree of difference between them. To investigate how different the observers' preferred flexion angle measuring methods were compared to the ISO 11226 Reference Posture, a virtual body model was constructed using the Poser 6.0 program. Six types of body flexion postures were constructed, and since neck flexion differs according to body angle, five types of neck flexion postures were constructed with the trunk bending $20^{\circ}$ forward, making up a total of 30 virtual flexion postures. Results: Results showed that the observers used personally preferred reference points instead of reference points recommend in the evaluation tools. Also the results revealed the their seems to be 6 types of flexion angle for the trunk and 11 types of measurement methods for the neck flexion angle in the form of personally preferred reference points. The results showed that a mean difference of $14^{\circ}$($4{\sim}23^{\circ}$) occurred in the trunk, and a mean difference of $20^{\circ}$($-8{\sim}51^{\circ}$) occurred in the neck. To increase accuracy when using the 5 evaluation tools in combination, the ISO 11226 standards, observers' preferred flexion posture standards, and common flexion posture standards of the evaluation tools were compared with the reference points of the 5 evaluation tools. Results showed considerable variance in angle difference for each evaluation tool. Conclusion: According to the results of this study, considering the angle difference between the flexion angle reference points of the evaluation tool and the reference points selected by the observers, it is concluded that instead of personally preferred reference points, the standardized reference points to enhance the accuracy and the objectivity. Application: The result of this study can be used as reference guide to develop the standardized reference point in the future.

• 대한인간공학회지
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• 제27권1호
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• pp.45-51
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• 2008

The purpose of this survey was to identify ergonomic risk factors of work-related musculoskeletal disorders (MSD) and understand the current MSD risk status in the wholesale/retail industry. The field survey was conducted at 120 wholesale/retail establishments, and the cause of MSD occurred from the national industrial accident statistics by the Ministry of Labor in 2006 was analyzed in terms of company size, a term of work, job title, and cause of occurrence. The numbers of disasters on MSD were 602 which were included 432 disasters who met with low back pain by incident. A checklist was developed by KOSHA to use for the field survey. A total of 419 tasks were identified at the 120 establishments surveyed. The highest frequency was Task 2(45%) which was mostly observed in repetitive work (e.g. displaying, scanning, cutting or wrapping of goods). The second and third were Task 9(34%) and Task 8(14%) which were identified in manual materials handling (e.g. lifting, lowering, carrying or stocking of goods). The results suggest that the three Tasks should be first considered for the control in wholesale/retail industry and that exposure to MSD risk factors in those Tasks should be primarily addressed in order to reduce MSD risk in that industry.

• Safety and Health at Work
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• 제10권3호
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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.

• 대한인간공학회지
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• 제30권4호
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• pp.481-489
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• 2011

Objective: The aim of this study was to develop an ergonomic checklist (AULA: Agricultural Upper-Limb Assessment) which can assess the risks of the work-related upper limb disorders of farming tasks in Korea. Background: There are few assessment tools that reflect the current condition of agricultural works as of now. Method: AULA was developed as following three stages. First of all, a physiological experiment was conducted with selected 14 upper limb postures which are frequently occurred in farming tasks and then, an ergonomic checklist was developed with determining risk levels of each body posture based on the experimental findings. Lastly, the ergonomic checklist was validated by comparing with the existing assessment tools. Results: When comparing the AULA which was developed in this study with the existing assessment tools, it was found that the AULA may get over limits of the existing ones which are sensitive to particular postures, but aren't sensitive to the rest of them. Conclusion: It is predicted that the developed upper limb posture assessment tool which gets over the existing tools' limits and is proper for domestic farm work conditions, will help to reduce musculoskeletal disorders caused by farm works, by assessing farm works more easily and objectively. Application: By further developing the theoretical groundwork on the induction of muscular skeletal system symptoms relating to agricultural works, it is expected to improve the level of preventing and managing such muscular skeletal system symptoms in the field of agricultural and farming works, which is relatively less advanced in terms of labor difficulties.

• Safety and Health at Work
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• 제9권3호
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• pp.239-248
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• 2018

Background: Workers may be exposed to various types of occupational hazards at the same time, potentially increasing the risk of adverse health outcomes. The aim of this review was to analyze the effects of multiple occupational exposures and coexposures to chemical, biomechanical, and physical hazards on adverse health outcomes among agricultural workers. Methods: Articles published in English between 1990 and 2015 were identified using five popular databases and two complementary sources. The quality of the included publications was assessed using the methodology developed by the Effective Public Health Practice Project assessment tool for quantitative studies. Results: Fifteen articles were included in the review. Multiple chemical exposures were significantly associated with an increased risk of respiratory diseases, cancer, and DNA and cytogenetic damage. Multiple physical exposures seemed to increase the risk of hearing loss, whereas coexposures to physical and biomechanical hazards were associated with an increased risk of musculoskeletal disorders among agricultural workers. Conclusion: Few studies have explored the impact of multiple occupational exposures on the health of agricultural workers. A very limited number of studies have investigated the effect of coexposures among biomechanical, physical, and chemical hazards on occupational health, which indicates a need for further research in this area.

• 대한인간공학회지
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• 제35권2호
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• pp.67-74
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• 2016

Objective: The aim of this study is to develop a farming shovel to reduce workload, which helps farmers lower the risk of musculoskeletal disease. Background: Most of work using farming tools including shovels requires repetitive works and awkward postures on body parts, and it could possibly cause work-related musculoskeletal disorders. It is necessary to develop and distribute farm equipment and tools in order to reduce physical workload. Method: To improve the most uncomfortable task perceived by ten farmers during the work with a shovel, the improved shovel was designed and made as a prototype for experiment for the comparison of the existing and improved shovels. Twenty males were recruited for this experiment, and muscle activity (%MVC) of six body parts and subjective discomfort ratings by body parts while working with a shovel were measured. A paired t-test was performed to compare physical workload between the existing shovel and the developed one. Results: A shovel applying foothold tied between shaft and blade was designed, which can help workers reduce repetitive bending of back and pressures for upper limbs while digging soil. According to compared evaluation of the developed shovel and the existing shovel, the developed shovel's %MVCs in all experimental muscles were significantly lower than those of the existing shovel. The developed shovel showed the biggest drop in perceived subjective discomfort rating of back, followed by arm and neck, compared to the existing shovel. Conclusion: It was confirmed that attaching a foothold to a shovel was an effective way of reducing workload in back and upper limbs during digging. Application: In the near future, if we put the prototype of developed shovel to practical use after making up for defects, it will help farm work environment be healthier and safer.

• 한국전문물리치료학회지
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• 제25권3호
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• pp.39-50
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• 2018

Background: High string instrument (violin, viola) players are at high risk for developing musculoskeletal problems. In particular, a higher prevalence of shoulder problems has been reported. However, evidence of the effectiveness of therapeutic exercise for musicians with this condition is lacking until now. Objects: This case series study investigated the effect of a specific exercise program on shoulder pain, dysfunction, and posture of professional orchestral high string musicians. Methods: Five professional orchestral high string players with shoulder pain participated in this study. A six-week specific exercise program focus on scapular stability for shoulder pain consisted of scapular muscle exercise. Physical examinations for pain and dysfunction, posture were performed, were identified among all subjects before starting the exercise program. Results: The results revealed that shoulder pain decreased by 67.86% and the effect of pain on instrument play decreased by 63.33%. The shoulder pain and disability Index and the performing arts module-quick disability of the arm, shoulder and hand scale decreased by 71.72% and 51.61% respectively. The exercise program improved function and posture. Conclusion: A specific exercise program for high string players was effective in managing shoulder pain. This case series is intended to provide empirical data on the effectiveness of an exercise program aimed at assessing the effect of exercise on pain, dysfunction, and posture of professional orchestra musicians associated with specific instrument groups.