The Study of Work and Rest Time Arrangement on Muscle Fatigue Recovery for a Repetitive Task of Upper Limbs

• Main Authors: Chang-You Wu, 吳長祐
• Other Authors: Cheng-Lung Lee
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/44174912900389115378

碩士 === 朝陽科技大學 === 工業工程與管理系碩士班 === 101 === Four main ergonomics factors to affect the upper limb musculoskeletal disorders are: awkward postures, overexertion, repetition and work/rest. However, few literatures have been emphasized on the work and rest time arrangement for upper limb repetitive tasks. An experiment was conducted to collect electromyographic data (EMG), force and heart rate when a simulated repetitive task was performed in the laboratory. Twelve young male subjects were recruited. Eight experimental factors were included：4 different rest time periods (0.25, 0.5, 1, and 1.5 times of work time of 9 min) and 2 different object loads (1 and 2 kg), in this study. The Viewlog software developed was used to calculate %MVC (maximum voluntary contraction, MVC) from electromyographic signals of tested muscles to explore the upper limb muscle fatigue recovery. The EMG results showed that the rest time period change might significantly affect the tested muscles. The EMG results, on rest time period of 0.25 times work time, obtained from biceps brachii, middle deltoid, and anterior deltoid, had the significantly different muscle fatigue recovery (p＜0.05) when compared with the other three rest time periods (the recovery more than 90%). The EMG results measured from triceps brachii on the rest time period of 1.5 times work time showed significantly different (p＜0.05) when compared with the other rest time periods. It was recommended rest time should be taken at 0.5 times of the working time, and the recovery might reach between 87.3% and 98.6%.