Abstract
Most researchers focused on estimating the mechanical stresses at particular joints to determine the potential of injuries in manual lifting tasks. Mechanical energy expenditure (MEE) could be an effective tool combined with the mechanical stresses to compare different manual lifting tasks. A lifting experiment was conducted to study the effect of the load, posture, speed, and technique of lifting on the total MEE. Eight male college students participated in the experiment. Four independent variables were studied. These were: (1) load lifted (7 Kg, 14 Kg, and 21 Kg), (2) lifting technique (stoop and squat), (3) speed of lifting (fast and slow), (4) torso twisting angle (0 degree and 90 degrees). Analysis of variance was performed on the total MEE. Results showed that the load lifted, lifting technique, and the speed of lifting had a statistically significant effect on the total MEE( alpha <0.01), while the torso twisting angle was not significant. The (torso twisting angle)*(speed of lifting) was the only significant interaction ( alpha <0.05).