Analysis of Center of Pressure Location during Asymmetric Lifting

We have an interest in the handling posture at the logistic workplace. Although a lot of studies on compressive and shear forces on lumbar spine have been reported, there was little studies on the difference of asymmetric lifting between logistic workers and beginners with the comparison of measured results. The main purpose of this study was to analyze the difference between ten healthy workers (Group 1) and five beginners (Group 2) during the asymmetric lifting through measurement of center of pressure (COP) locations. We performed experiments to move the 18 kg load to the left side under the condition of closed eyes. Through analysis results of COP locations, we found that Group 1 had the difference from Group 2. Most of COPs of Group 1 was located in the right side during the trunk angle to twist to the left side. We reported all of experimental results in this study.

I. Introduction

We have an interest in the handling posture during the asymmetric lifting at the logistic workplace [1]–[4]. A lot of studies on compressive and shear forces on lumbar spine during the asymmetric lifting have been reported [5], [6]. Those mentioned the more increased compressive and shear forces on lumbar spine during the asymmetric lifting through analysis results of measured trunk angle and biomechanical model. If so, we have a question about what is the difference of asymmetric lifting between healthy worker and beginners. What is the knowhow of workers at the logistic workplace under the condition of the more increased forces on lumbar spine in order to reduce the burden of waist? [15].