• The Journal of Korean Physical Therapy
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• 제21권1호
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• pp.57-63
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• 2009

Purpose: We determined the recruitment pattern of lumbar elector spinalis, gluteus maxims, inner and outer hamstring muscle during trunk flexion and extension. Methods: Thirty healthy subjects(male; 15, female; 15) without low back pain and other problems in lower extremities participated in this study. To measure the recruitment pattern, the onset times of electromyographic activity of the muscles were recorded during trunk flexion and return(extension) to standing position. Results: The medial and lateral hamstring muscle was activated first, next elector spinalis, the last, gluteus maximus in trunk flexion. In trunk extension to standing position, the order of recruitment was similar to trunk flexion although the frequency is different. There were different between male and female in flexion and extension movement. Conclusion: The recruitment order of lumbar extensor and hip extensors in trunk flexion and extension will provide database in evaluation and intervention of lower back pain and lumbo.pelvic rhythm disorder.

• 대한인간공학회지
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• 제22권4호
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• pp.47-57
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• 2003

This study investigated the recruitment patterns of ten trunk muscles in isometric exertion tasks, focused on the functional roles (agonist or antagonist). Twelve male students performed maximum voluntary isometric exertion tasks towards six directions: flexion/extension, left/right lateral bending, and clockwise/counter-clockwise twisting. EMG signals from ten trunk muscles and exertion forces were collected. Normalized EMG (NEMG) values were calculated at 10, 20, 30, 40, 50, 60, 70, 80, and 90 %MVC. The subjects showed a limited capacity in producing twisting moments, approximately 50% of the extension moment, and 70% of lateral bending moments. EMG activity was dependent on the direction and magnitude of the exertion, and also on the functional role. The mean NEMG of agonist was 0.260 and 0.067 for antagonist. Agonists showed the highest mean NEMG in flexion (0.367), while antagonists showed the highest mean NEMG in twisting clockwise/counter-clockwise (0.090/0.106).

• 대한산업공학회지
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• 제24권2호
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• pp.261-278
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• 1998

The paper represented the lower extremity muscle model as four rigid-body segments: trunk, shank, and foot. We transformed their tibial data into our shank data by rotating their tibial X and Y axes by 5.483 degrees, so the revised coordinate data used to translating the origin of their tibial reference frame to our shank reference frame. According to weight of subject, physiological cross-setional area(PCSA) of each lower extremity muscle was calculated by scaling those data by Brand. The objectives of this paper are to investigate the variations of the recruitment patterns of the lower extremity muscles, and to analyze the changes of the role assigned to each muscle during the seated foot operation. For exertion levels, the transition point of type F motor unit of each muscle is inferred by analyzing the electromyogram at the seated postures. Also, for predetermined seated foot operations exertion levels, the recruitment pattern and the changes of the role assigned are identified in the continuous exertion, by analyzing the electromyogram changes due to the accumulated muscle fatigue. This study can be used to design and to assess the pedals and foot-related equipments design.