작업 중 여유시간 변화에 따른 몸통 근육 누적 피로도

Abstract

The purpose of this study was to identify the relationship between the cumulative fatigue of trunk muscles and the period of recovery time during repetitive lifting and lowering tasks with symmetric and asymmetric postures. Ten subjects participated in the experiment. Subjects had 1, 2, 3, 4 and 5 minutes recovery time respectively while they were performing the lifting and lowering task repeatedly for 3 minutes with the weight equivalent to 25% level of MVC. EMG signals from ten trunk muscles were collected and the fatigue level was analyzed quantitatively. In results, the local muscle fatigue was no longer accumulated when 5 minutes recovery time was given in symmetric position. For asymmetric position, it took longer minutes to prevent the fatigue accumulation. Different trunk muscles indicated slightly different recovery patterns in terms of MPF (Mean Power Frequency) value. This result would help ergonomist design the length of recovery time to control the cumulative fatigue of trunk muscles in industry with repetitive lifting and lowering task.