Repeat Exposure to Leg Swing Perturbations During Treadmill Training Induces Long-Term Retention of Increased Step Length in Human SCI

Abstract

OBJECTIVE: To determine whether repeat exposure to force perturbations during treadmill training can induce long-term retention of improved step length and overall improvements in locomotor function in persons with spinal cord injury. DESIGN: Fourteen patients with spinal cord injury were recruited and randomly assigned to swing resistance or swing assistance training groups. A controlled swing resistance or assistance force, for resistance or assistance training groups, respectively, was applied to both legs through a cable-driven robotic system during treadmill training. Each participant trained 3 times per week for 6 weeks. Step length, walking speed, 6-minute walking distance, and other clinical assessments were evaluated before and after 6 weeks of training and 8 weeks after the end of training. RESULTS: A significant increase in step length was observed after 6 weeks of resistance training (P = 0.04). Step length tended to increase after assistance treadmill training, but the change was not significant (P = 0.18). The changes in step length and functional gains had no significant difference between 2 groups. CONCLUSIONS: Repeat exposure to swing resistance during treadmill training may induce a prolonged retention of increased step length, although it remains unclear whether swing resistance versus assistance is more effective in inducing increased step length.