Electromyographic signal of local active muscles in automobile assembly workers

Objective To analyze the electromyographic signal of local active muscle in automobile assembly workers with surface electromyography (sEMG),in order to explore the causes of musculoskeletal disorders (MSD).Methods Six male workers in automobile assembly department were selected.The operation of pneumatic wrench fastening bolt was selected as the referenced action.sEMG signals of shoulder and wrist muscle groups were recorded with a mobile electromyologram.Results The assembly operation was a work of light loading.During working-time,there were no significant changes in root mean squares (RMS) and median frequence (MF) on the tested muscle groups.The time course curves of MF on shoulder muscles revealed the similar tendency(r=0.902,P0.05),which was increased first,and then decreased.Conclusion During working-time,the fatigability of shoulder muscles increased significantly.