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

Abstract

Twelve young adults (six males—mean age 24.1 years, mean weight 75.4 kg and mean height 176.6cm—and six females—mean age 20years, mean weight 59.8kg and mean height 162.6cm) lifted and lowered a weight of 10 kg from a height of 13.5 cm at three-quarters reach. The weight was lifted and lowered in the sagittal, 30° lateral and 60° lateral plane by stoop, squat and free-style techniques six times per minute for a period of 4min, and the subjects rested for a period of lOmin. The steady-state values of oxygen consumption during these activities were measured. The subjects also subjectively assessed the relative degree of tiresomeness of the tasks studied. The oxygen 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 oxygen and had the lowest per-minute inspiratory ventilation volume. The squat method required the highest oxygen 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 free style least tiring of the three techniques studied.