Ph.D Thesis

Ph.D StudentHaim Amir
SubjectPlasticity of Gait Patterns via Noninvasive Biomechanical
DepartmentDepartment of Mechanical Engineering
Supervisors PROF. Alon Wolf


Motor tasks such as walking are attained via execution of "motor patterns", a collection of neuro-muscular commands, stored in the central nervous system, convening a volley of kinematic trajectory commands to the skeleto-muscular instruments which generate the appropriate kinetics. Motor patterns are purchased in an implicit manner and are continually "fine-tuned" via afferent stimuli. Extensive evidence indicates that motor program adaptations may compensate for losses in mechanical integrity through altered movement and muscle activation patterns. Moreover, recent advances suggest that the nervous system can be modeled and shaped by appropriate patterns of peripheral inputs.

Various footwear-generated biomechanical manipulations have been shown to influence the kinetic activity of the lower limb. These interventions utilize the principle that the parts of the body act as a system of chained links, whereby the whole limb is regarded as one kinetic unit. Two main types of non-surgical biomechanical interventions are available: first is the “passive” type which is designed to directly influence (unload) the articular surface; second is the “active” type that aims to improve neuromuscular control skills.

The current study was devised to study the routes that underlie locomotor adaptations induced by controlled biomechanical stimulation. A novel foot-worn device comprising four modular elements was utilized. We elected to focus on patients suffering from medial compartment knee osteoarthritis. Abnormal gait patterns are characteristic of advanced disease and contribute to the diminished functional capability and excessive loading of the affected joint.

Our working hypothesis was that controlled external stimuli via external manipulation would give rise to modified gait patterns. During the course of the study, the model was tested on healthy volunteers as well as on patients suffering from medial compartment knee OA.

Gait analysis and elctromyographic examinations of participants demonstrated a direct correlation between the locus of the foot's center of pressure (in both the sagittal and coronal planes) and kinematic, kinetic and elctromyographic gait parameters. Similarly, it was demonstrated that prolonged and repeated exposure to such training can give rise to subjective and objective favorable outcomes in patients with knee OA. The most striking result was modification and reduction of the knee adductor moment and alterations in muscle activation patterns in the lower limbs. The results of this study contribute to the understanding of OA pathogenesis and treatment. Implementation of these principles could lead to a change in the conventional treatment of this disease and of similar pathologies.