Prediction models for psychophysical lifting capabilities and the resulting physiological responses for work shifts of varied durations

This paper presents models for predicting estimates of maximum weights of lift acceptable to industrial workers for 8-hour work shifts. Prediction models are also presented for heart rate and oxygen uptake at the maximum acceptable weight of lift. Experimental data collected on 37 males and 37 females were used in developing and verifying these models. Each subject performed nine variations of a lifting task involving three heights, four frequencies, and three box sizes to determine estimates of acceptable lifts for 8-hour shifts. The final lifting capability prediction models explained 76 to 82% variance in the experimental data. A procedure is also described to determine, from these models, acceptable lifts for work periods of variable lengths. The physiological-response-prediction models, which provide estimates of heart rate and oxygen uptake at the maximum acceptable weight of lift, were, however, relatively inferior to other similar response models available in the literature. This is thought to be due to the differences between the psychophysical and physiological methodologies.