Differences between Lifting and Lowering Manual Material Handling Tasks in Distribution Centers

Abstract

A cross-sectional study was conducted to quantify the physical demands of manual material handling in distribution centers. One hundred and sixty-three workers were assessed wearing the moment monitor. The moment monitor measures static and dynamic mass of the boxes as well as the trunk kinematics and moment arms of each manual material handling exertion. The moment monitor analysis software distinguishes between lifting, lowering, pushing/pulling exertions. Paired comparison between lifting and lowering were performed on 163 workers. The results showed no differences in static mass or moment whereas the dynamic z force and dynamic moment were significantly greater for lifting. Trunk kinematic results showed greater sagittal velocity for lifting compared to lowering but greater lateral velocity for lowering compared to lifting.

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