Adaptation to Knee Flexion Torque Assistance in Double Support Phase

Studies have shown locomotor adaptation of the ankle to assistive torques, but the ability of the knee to adapt to assistive forces has not yet been explored. Understanding how humans modulate knee joint kinematics during gait could be valuable for designing assistive devices for stroke patients. In this study we examined how healthy subjects adapt to knee flexion torque assistance during gait. We hypothesized that subjects would adapt to flexion assistance by returning knee flexion kinematics to near baseline values, followed by substantially reduced kinematics once the assistance forces were removed. Data from the five subjects show a weak adaptation, and an increase in knee flexion kinematics after forces were removed, contrary to expectations. These results suggest that neuromuscular control of the knee joint during walking is not strongly modulated.