Symmetrical Leg Behavior during Stair Descent in Able-bodied Subjects

Abstract

An evaluation of asymmetry in human gait is an important step towards clinical evaluation and developing the rehabilitation treatment for pathological gait. Although asymmetry of lower extremity actions during level walking was well established, little is known about stair walking. The purpose of this study was to compare bilateral lower limb mechanics during stair descent in able-bodied subjects. Ten male subjects (age = 27.6 ± 2.2 years; height = 1.73 ± 0.56 m; mass = 65.0 ± 8.6 kg, mean ± SD) with no neuromuscular disorders or functional limitations in their lower limbs participated in the study. Subjects were instructed to walk down a laboratory staircase without handrail use at self-selected speed. Each step in this staircase had a height of 16 cm, a depth of 30 cm, and a width of 80 cm. Sagittal plane kinematics and ground reaction forces were collected and lower extremity stiffness was calculated as the ratio of peak vertical ground reaction force to peak leg compression during early stance phase. The lower extremity stiffness were 17.8 ± 4.1 kN/m for the dominant leg and 18.2 ± 5.3 kN/m for the nondominant leg; there was no significant difference between them. There was also no significant difference in both the peak vertical ground reaction forces (dominant; 1.06 ± 0.17 kN, non-dominant; 1.08 ± 0.19 kN) and peak leg compressions (dominant; 0.06 ± 0.01 m, non-dominant; 0.06 ± 0.02 m) between the legs. The results of the present study suggest that the lower extremity of able-bodied subjects during stair descent behaves symmetrically. © 2009 International Federation of Medical and Biological Engineering.