The Effect of Cycle Time Reduction on Upper Trapezius Muscle in Light Assembly Task

摘要

Electronic industry is the leading industry in manufacturing sectors and one of the largest employers in Malaysia. A cross sectional survey in electronic (semi conductor) industry shows that assembly line workers had the highest prevalence of neck/shoulder and upper back pain. This study aims to elucidate the effect of cycle time reduction in Upper Trapezius muscle in simulated light assembly task using LEGOTM construction block. Eight subjects (4 males and 4 females) were participated in this study. Electromyography (EMG) activity of upper trapezius muscle was recorded for one hour. Subject used dominant hand to pick the pieces of LEGOTM and assemble with the plate. The experiment done twice (separate in one day) in different cycle time, three seconds and five seconds cycle time. Root mean Square (RMS) of EMG data was analyzed using SPSS v.15. Paired-sample T-test was used to investigate the significant effect of cycle time. The result shows that there is a significant effect of reduction cycle time in Upper Trapezius muscle in light assembly task.