The Effects of Coordinated Upper-limb Postures of Back, Shoulder, and Elbow Flexion Angles on the Subjective Discomfort Rating, Heart Rate, and Muscle Activities
- Authors
- Kong, Yong-Ku; Lee, Soo Jin; Lee, Kyung-Suk; Seo, Min-Tae
- Issue Date
- Dec-2011
- Publisher
- 대한인간공학회
- Keywords
- WMSDs; Ergonomics evaluations; Back flexion angle; Shoulder flexion angle; Elbow flexion angle
- Citation
- 대한인간공학회지, v.30, no.6, pp.695 - 703
- Indexed
- KCI
- Journal Title
- 대한인간공학회지
- Volume
- 30
- Number
- 6
- Start Page
- 695
- End Page
- 703
- URI
- https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/166727
- DOI
- 10.5143/JESK.2011.30.6.695
- ISSN
- 1229-1684
- Abstract
- Objective: This study was to investigate the effects of coordinated upper-limb body postures on the subjective discomfort rating, heart rate, and muscle activities. Background: Although generally many checklists such as OWAS, RULA, and REBA were applied to evaluate various body postures, the body postures were might be overestimated or underestimated because each body part(i.e., back, shoulder, and elbow etc.) was evaluated separately, and then added all rates of individual body parts to assess an overall risk level for the body posture in these methodologies. Methods: A total of 20 participants maintained 14 postures which were combinations of back, shoulder, and elbow flexion angles and then muscle activities, subjective discomfort, and heart rates were collected every three minute during a sustained 15 minute and 0.5kg weight holding task. Four muscle groups were investigated: erector spine, anterior deltoid, upper trapezius, triceps brachii. Results: Results showed that subjective discomfort was the lowest when the angle of back and shoulder were both 0°s, while the body posture with 45° of back angle and 45° shoulder angle was rated as the most subjective discomfort posture. In general, the subjective discomfort ratings increased as back and shoulder flexion angles increased. It was noted that, however, the
subjective discomfort of body posture with a 45° back angle and 45° shoulder flexion angle was lower than that of body posture with a 0° back and 45° shoulder flexion angle. The research findings of heart rates and muscle activities showed similar results for the analyses of subjective discomfort ratings. Conclusions: The possible limitations of the current ergonomics evaluation techniques which assessing a body posture with summing all body part score after individually analyzed in this study. Based on the analyses of subjective discomfort, heart rate, and muscle activities, it was recommended that a use of effects of coordinated upper-limb body postures would be considered when one evaluates work-load for various working postures. Application: These findings can be used for developing a more accurate assessment checklist for working posture as well as preventing musculoskeletal disorders of workers in workplaces.
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Collections - 서울 의과대학 > 서울 직업환경의학교실 > 1. Journal Articles
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