|M.Sc Student||Goryachev Yulia|
|Subject||Influence of Footwear-Generated Biomechanical Manipulations|
on the Muscle Activity of the Leg
|Department||Department of Mechanical Engineering||Supervisor||Professor Alon Wolf|
|Full Thesis text|
Foot orthoses have been widely used to successfully treat a range of pathologies related to biomechanical dysfunction of the lower limb. The foot orthoses (FO) are commonly used to reduce the elevated joint moments and by so to improve the joint status. Previous studies have proposed biomechanical theories for FO hypothesized that the mechanism of reduction of adduction moment of the knee with the use of FO is a shift in the center of pressure (COP). We hypothesized that the change in joint kinetics is also supported by a change of muscle activity in the lower extremity. Such changes could have positive implications in reducing muscle fatigue and overuse injuries of the lower extremity.
The purpose of this study was to investigate the effect of different COP positions during gait on the electromyography (EMG) of the lower limb musculature of healthy subjects and subjects with knee osteoarthritis (OA). For the OA subjects EMG signal after prolonged gait therapy combining patient specific COP manipulation was also examined. A novel foot-worn biomechanical device (APOS Therapy) that combines controlled manipulation of the COP during gait with balance perturbation was used. Both for the healthy and OA subjects the EMG signal was found to significantly alter immediately after COP manipulation, the effect was more prominent for the healthy subjects. The nature of change in the muscle activation was correlated to the COP modification. Muscle activation counteracted the disturbance induced by the COP shift, in order to maintain stability in the lower kinematic chains. When combined with a prolonged therapy program, the muscle activity of OA subjects in barefoot walking was found to be increased and the activity duration tended to decrease indicating more effective walking strategies and motor learning. The favorable muscle activation patterns were associated with improved kinetic and kinematic parameters, reduced pain and elevated functionality.