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The Effects of Coordinated Upper-limb Postures of Back, Shoulder, and Elbow Flexion Angles on the Subjective Discomfort Rating, Heart Rate, and Muscle Activities
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 Title & Authors
The Effects of Coordinated Upper-limb Postures of Back, Shoulder, and Elbow Flexion Angles on the Subjective Discomfort Rating, Heart Rate, and Muscle Activities
Kong, Yong-Ku; Lee, Soo-Jin; Lee, Kyung-Suk; Seo, Min-Tae;
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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 , while the body posture with of back angle and 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 back angle and shoulder flexion angle was lower than that of body posture with a back and 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.
WMSDs;Ergonomics evaluations;Back flexion angle;Shoulder flexion angle;Elbow flexion angle;
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Chaffin, D. B., Andersson, G. B. J. and Martin, B. J., Occupational Biomechanics, 3rd ed., John Wiley & Sons, Inc., New York, 1999.

Fox III, S. M., Naughton, J. P. and Haskell, W. L., Physical activity and the prevention of coronary heart disease, Annals of Clinical Research, 3, 404-432, 1971.

Genaidy, A. M., Al-Shedi, A. A. and Karwowski, W., Postural stress analysis in industry, Applied Ergonomics, 25(2), 77-87, 1994. crossref(new window)

Hignett, S. and McAtamney, L., Rapid entire body assessment(REBA), Applied Ergonomics, 31, 201-205, 2000. crossref(new window)

Karvonen, M. J., Kentala, E. and Mustala, O., The effects of training on heart rate: a longitudinal study, Annales Medicinae Experimentalis Et Biologiae Fenniae, 35(3), 307-315, 1957.

Kilbom, A., Assessment of physical exposure in relation to work-related musculoskeletal disorders - what information can be obtained from systematic observations?, Scandinavian Journal of Work Environment and Health, 20, 30-45, 1994.

Li, G. and Buckle, P., Current techniques for assessing physical exposure to work-related musculoskeletal risks, with emphasis on posture-based methods, Ergonomics, 42(5), 674-695, 1999. crossref(new window)

Lim, C. M., Jung, M. C. and Kong, Y. K., Evaluation of upper-limb body postures based on the effects of back and shoulder flexion angles on subjective discomfort ratings, heart rates, and muscle activities, Ergonomics, 54(9), 849-857, 2011. crossref(new window)

Kong, Y. K., Kim, D. M., Han, J. G. and Lim, C. M., Evaluations of subjective and objective measurements for back and shoulder postures, 2010 spring conference of Ergonomics Society of Korea, (pp. 181-184), Jeju, 2010.

Korea Occupational Safety & Health Agency (

McAtamney, L. and Corlett, E. N., RULA: a survey method for the investigation of work-related upper limb disorders, Applied Ergonomics, 24, 91-99, 1993. crossref(new window)

McGill, S. M. and Norman, R. W., Partitioning the L4-L5 dynamic moment into disc, ligamentous, and muscular components during lifting. Spine, 11, 666-678, 1986. crossref(new window)

Park, D. H., Ergonomic risk factors of musculoskeletal disorders related to agricultural work, Rural living science, 21(2), 59-67, 2000.

Perotto, A., Anatomical Guide for the Electromyographer: The Limbs and Trunk, 4th Edition, Charles C Thomas Publisher, Ltd., Springfield, Illinois, USA, 2004.


Winkel, J. and Mathiassen, S. E., Assessment of physical work load in epidemiologic studies: concepts, issues and operational considerations, Ergonomics, 73(6), 979-988, 1994.