Kinematics of cart pushing and pulling under different loads and surface gradient conditions

Abstract

Background: Manual material handling incidents are responsible for a large portion of lost work days annually. With the transition to e-commerce, cart pushing and pulling tasks have become more common. Objective: This research explored the effects of surface gradient and load on full body kinematics during cart pushing and pulling tasks. Methods: Ten participants were recruited to complete two sets of tasks. Participants performed cart pushing tasks on three surface gradients and three load masses and downhill cart pulling tasks on two surface gradients and three load masses while being recorded with an optical motion capture system. Full body, three-dimensional joint angles were calculated for each task, and peak angles of the major body joints were analyzed using general linear models to determine the effects of the dependent variables. Results: During the cart pushing tasks, increased load mass and surface gradient both caused a significant increase in the peak joint angles of most body joints with surface gradient having the larger effect. When cart pushing and pulling tasks were compared with 5° and 10° surface gradients and three load masses, cart pushing resulted in significantly higher joint angles. Conclusion: During manual material handling tasks involving a cart, surface gradients and load masses should be minimized.