Effect of lower limb on body propulsion.

The purpose of this study was to analyze and compare the effects of the leg during swing and stance phases of forward propulsion of the body for both men and women. Twelve able-bodied subjects, six men and six women, were studied with a Vicon(a) gait-analysis system. A two-dimensional, sagittal-plane biomechanical analysis featuring a link-segment model was used to determine the force at the hip in the horizontal direction. Integrating this force curve over time during the swing and stance gait phases produced linear impulses, representing swing and stance contributions to the propulsion of the body, and it allowed quantitative comparisons using student t and Fisher tests. The deceleration of the swing leg was found to be the major contributor to the forward propulsion of the body. The stance leg initially exerted the major restraining or negative impulse during early stance; then it generated a positive impulse during push-off in late stance. A typical pattern of gait impulses was defined for normal gait. Male and female gait impulses were not significantly different for all gait phases.