Kim S H, Chung M K
Department of Industrial Engineering, Pohang University of Science and Technology, Korea.
Ergonomics. 1995 May;38(5):853-63. doi: 10.1080/00140139508925156.
We examined the effects of posture, weight and frequency on trunk muscular activity and fatigue during repetitive dynamic lifting. Electromyographic (EMG) signals from eight primary trunk muscles were collected during 120 min for four different task conditions. The patterns of muscle recruitment and the levels of relative activation were analysed using the normalized EMG data. Median power frequency (MPF) shift patterns were analysed to examine muscular fatigue. The muscles in the dorsal part of the trunk were activated at the symmetric posture, while the muscles on the contralateral side to the workload were more strongly activated at the asymmetric posture. Decreasing trends of MPFs were found in some active muscles, and they were more pronounced for the asymmetric posture than for the symmetric posture. It was also seen that the muscles became fatigued faster for the light load-high frequency task than for the heavy load-low frequency task.
我们研究了姿势、重量和频率对重复动态举重过程中躯干肌肉活动和疲劳的影响。在120分钟内，针对四种不同任务条件，采集了来自八块主要躯干肌肉的肌电图（EMG）信号。使用归一化的EMG数据对肌肉募集模式和相对激活水平进行了分析。分析了中位功率频率（MPF）的变化模式以检查肌肉疲劳。在对称姿势下，躯干背部的肌肉被激活，而在不对称姿势下，与负荷相对侧的肌肉激活更强。在一些活跃肌肉中发现了MPF的下降趋势，并且不对称姿势比对称姿势更明显。还发现，与重负荷-低频率任务相比，轻负荷-高频率任务中肌肉疲劳更快。
