Psychophysical models for manual lifting tasks

This paper provides two models for males and females to assess the psychophysical maximum acceptable weight of lift. The weight guidelines generated by the models are a function of lifting frequency, height of lift, sagittal or asymmetrical lifting, task duration, container size in the sagittal plane, presence or absence of container couplings, and percentage of the working population. The developed models were generated from a knowledge base available in the published literature. A computer program was written in BASIC to assist the user in determining the safe load that could be handled by a specified working population. Model validation showed that the models developed predict the maximum acceptable weight of lift with a reasonable degree of accuracy. A comparison between the National Institute for Occupational Safety and Health recommendations and those made on the basis of the models developed in this paper is also presented.