The physiological cost of three different methods of lifting in sagittal and lateral planes

Abstract

Twelve young adults (6 men-mean age 24.1 yr, mean weight 75.4 kg and mean height 176.6 cm; and 6 women, mean age 20 yr, mean weight 59.8 kg and mean height 162.6 cm) lifted and lowered a weight of 10 kg from a height of 13.5 cm, at 3/4 reach. The weight was lifted and lowered in the sagittal, 30.degree. lateral and 60.degree. lateral plane by stoop, squat and freestyle techniques 6 times/min for a period of 4 min, and the subjects rested for a period of 10 min. The steady-state values of O2 consumption during these activities were measured. The subjects also subjectively assessed the relative degree of tiresomeness of the tasks studied. O2 consumption for each of the techniques was significantly different from the others (P < 0.01). The stoop method of lifting required the least amount of O2 and had the lowest per-minute inspiratory ventilation volume. The squat method required the highest O2 consumption and inspiratory ventilation volume. The plane of the activities did not have a statistically significant effect on the energy consumption. The squat method of lifting was subjectively rated most tiring, and freestyle least tiring of the 3 techniques studied.