Biomechanical analysis of two methods of descending stairs

Abstract

The activity of descending stairs increases loading at the joints of the lower extremities (Andriacchi et al., 1980) as compared to walking (McFadyen and Winter, 1988), which may cause certain discomfort and or difficulties in completing the task. This study compared and contrasted the kinematics and kinetics of forward and backward stair descent to Winter's level walking (1991). We compared the support moments and moment powers of the lower limb joints while descending stairs and secondly, performed an analysis of the position of the foot on the step (ground reaction forces) to determine which method was more likely to reduce the risk of slipping. Larger double peak support moments with reduced ankle plantar flexor and increased knee extensor moments were found. The hip moments were relatively small and highly variable. There was a significantly reduced peak knee extensor eccentric power (P = 0.005) with backwards descent. These results demonstrate that stair descent (forward and backward) required higher moments at the knee than level walking but backward descent demanded less peak knee moment and eccentric power than forward descent. Overall, the use of a backward approach, offer an alternative for people unable to access stairs in the forward fashion. (Abstract shortened by UMI.)