RESUMO
OBJECTIVES: The purpose of this study was to examine the electromyographic activities of the erector spinae muscle of the back and the rectus femoris muscle of the thigh, and to measure the angles of the spinal and knee flexions in order to determine the effect of wearing a back belt. METHODS: Fifteen healthy males participated in the study. Surface electromyography was used to measure the level of muscle activities at the two muscle groups. The Simi system, utilizing two-dimensional analysis of movement, was used to examine the range of motion of the back and low extremity. RESULTS: Firstly, the angle of the spinal flexion was significantly less in the back-belt-wearing group than in the control, and that of the knee flexion was significantly increased in the back-belt-wearing group. Secondly, there was no significant change in the electromyographic signals of the erector spinae muscle of the back and the rectus femoris muscle of the thigh. CONCLUSIONS: The use of back belts helps workers to correct their posture when lifting boxes. It can therefore protect workers from acute back injuries.