Task parameters affecting human physical ability and willingness to lift: An ecological approach
Abstract
The objective of this study was to analyze human perception of load heaviness in manual material handling tasks under varying task parameters taking into consideration participants' physical ability and willingness to lift loads. These conditions were: 1) box color, 2) instruction set, and 3) space confinement. The effect of each parameter on the maximum acceptable weight that people are willing to lift was investigated. This study showed that the box color significantly affects a participant's perception of weight. The average maximum acceptable weight participants were willing to lift was higher for the black boxes than for the white boxes in both open and constrained spaces. When using the white boxes, the maximum acceptable weight participants were willing to lift was smaller in the confined space than in the open space. This study introduces an ecological approach to manual handling tasks and proposes the paradigm of maximum acceptable weight of load (MAWL) to the maximum loads that people perceive they are able and willing to lift (MLWL).
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