GAIT ADAPTATIONS OF YOUNG-ADULT FEMALES TO HAND-HELD LOADS DETERMINED FROM GROUND REACTION FORCES

Although walking with hand-held loads is a fairly mundane activity performed by all sections of the ambulant population, very few studies have been made of the possible consequences for the gait. In this study we investigated a group of young adult females while walking without load, asymmetrically loaded with 15% body weight either in the left hand or in the right hand, or symmetrically loaded with 15% body weight in each hand. Walking speed over a distance of 3.5 m was measured, together with data from two force plates. The latter were used to determine durations of the walking cycle and its phases. The ground reaction forces were incorporated in simple equations of motion to determine the oscillations of movement of the centre of mass of the body, or body plus load, during the walking cycle1. Group mean values of measurements made in the loaded situations were compared with the corresponding values for the unloaded situation. Values obtained for the asymmetric loading were used to investigate the effects upon gait symmetry. Our main findings were that loading tended to decrease the cycle duration, increase double support and decrease single stance phase, but the stance phase was not affected. The amplitudes of the lateral and fore-aft oscillations of the centre of mass were reduced by loading. Consistent asymmetries were seen in the body centre of mass oscillations as a result of asymmetric loading. Where comparisons are possible, our results tend to match those of other authors who performed studies under other sorts of loading conditions. The overall conclusion is that the changes even when significant are quite small, indicating that the gait adapts well to loading, at least for the group of subjects we studied and for the loads we used.