Evaluation of the dynamic stability of individuals with spinal cord injury

Abstract

BACKGROUND: Stability is the ability of subjects to keep his body in a stable position and has an ability to return from an unstable to a stable position. Although the stability of spinal cord injury (SCI) individuals has been evaluated in some research studies during quiet standing, none of them can be used to predict risk of falling, due to lack of relationship between static and dynamic stability. OBJECTIVE: The aim of this study was to evaluate the stability of SCI during walking. METHODS: Three groups of normal subjects, complete SCI walking with orthosis, and incomplete SCI participated in this study. Their dynamic stability was evaluated based on the motion of center of mass (COM) in the mediolateral and vertical directions normalized to the width of base of support and leg length, respectively. Two sample tests were used to evaluate the dynamic stability of the participants. RESULTS:There was a significant difference between the excursion of COM in vertical direction between normal, complete and incomplete SCI subjects (P-value < 0.05). However the difference between the COM movements in the mediolateral direction was not significant. The width of base of support of complete SCI was nearly two times more than that of normal subjects. CONCLUSIONS: SCI individuals increased their walking stability in mediolateral direction by increasing the base of support. The greatest movement of COM in vertical direction in SCI was due to specific gait strategy employed by SCI subjects. SCI subjects decrease their walking speed as a main strategy to improve their dynamic stability.