thesis

Effects of a simulated motion environment upon the physical demands of heavy materials handling operators

Abstract

Maritime shipping, commercial fishing, passenger and cargo shipping and offshore oil and gas industries are all major contributors to the economies of Atlantic Canada. These industries require workers to perform heavy materials handling under harsh environmental conditions, particularly extreme deck motions. The purpose of this study was to better understand the demands of a moving environment on the ability of a person to perform specific lifting tasks. -- Nineteen healthy male subjects volunteered for this study. Each subject was required to lift a 15 kg load under four lifting conditions. While performing these lifting tasks, a ship's motion simulator was used to create deck motions under foot. Three deck motions were considered: pitch, quartering and roll. A stable laboratory condition was also collected for all lifting conditions. Electromyography (EMG) histories of four muscles (erector spinae, latissimus dorsi, external oblique and trapezius) were collected bilaterally and thoracolumbar kinematics was measured throughout the experimental protocol. -- A repeated measures ANOVA was employed to assess trunk motions and muscle activities across the lifting and motion conditions. There were no significant differences found due to the motion effect for any of the muscles monitored in this study. However, the lifting task did produce differences in the EMG activities for some muscles. The maximal sagittal velocities were significantly smaller for all motion states in comparison to the stable lab condition (p≤0.01) while maximum twisting and lateral bending velocities increased in the motion conditions compared to the stable lab condition (p≤0.05). Results suggest that working in a moving environment will likely increase the operator's risk for overexertion injuries, particularly to the spine

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