Comparative analysis of the workload in seated and standing horizontal submaximal lifting tasks.

The objective of the present laboratory study was to analyse physiological responses of horizontal lifting tasks when they were performed in sitting and standing positions. Heart rate and blood pressure were used as indices of circulatory strain. Lifting tasks were performed under four lifting positions: sitting-forward lift, sitting-twist lift, standing-forward lift, and standing-twist lift. The weights of the loads were 3, 5 and 7 kg and the frequencies of handling were 1, 4 and 6 lifts/min. This study supports the idea that heart rate is a sensitive measure for evaluating the effects of seated horizontal lifting tasks. The lifting positions and workload (frequency x load x distance) are important parameters in the design of these types of tasks. It appears that within the experimental values examined in this study, a seated position could be recommended while performing horizontal lifting tasks at workloads < or = to 4.6 kg.m.min-1. The results are supported by smaller physiological responses.