Stroke is a leading cause of serious long-term gait disability in the elderly. The central nervous system (CNS) is believed to use the abundant degrees-of-freedom (DOF) of muscles and joints in stabilizing a particular task variable important for task success such as footpath in walking, which may be altered following stroke. However, it is not known if the current gait training paradigms can improve the muscle or joint coordination during walking post-stroke. Furthermore, there is a lack of strong evidence supporting the effectiveness of one specific locomotion intervention for functional gait recovery after stroke. The overall goal of this study was to compare the effects of robot-aided gait training (RAGT) using an “assist-as-needed” paradigm with the body weight supported treadmill training (BWSTT) on functional walking ability and footpath coordination during walking post-stroke.

In the first aim I identified the role of groups of co-activated muscles (i.e., muscle modes) in stabilizing the footpath during walking in stroke survivors and their age and gender matched healthy controls, using the uncontrolled manifold (UCM) approach. Both healthy individuals and stroke survivors had a significantly greater mode variance that lead to a consistent footpath than mode variance leading to an inconsistent footpath. However, there were no significant differences between groups in the ability to stabilize the footpath. These results suggested that footpath is an important task variable during walking that is stabilized by the CNS in healthy and stroke population. In addition, stroke survivors may be able to stabilize their footpath equally well as healthy individuals.

The second and the third aims investigated whether there are differences in the effects of “assist-as-needed” RAGT versus BWSTT on improvements in gait parameters and footpath stabilization. I implemented a performance based RAGT which encourages subjects’ active participation and compared its effects with more widely used but labor intensive BWSTT. Subjects demonstrated improvements in their functional walking ability following RAGT and BWSTT evidenced by improvements in some of the gait parameters. Subjects receiving BWSTT also demonstrated improvements in their ability to stabilize the footpath. Though, no significant differences between the groups were seen, but RAGT may be used as an alternative gait rehabilitation method as it requires less physical effort of the therapists compared to BWSTT.

Overall this dissertation work suggested that healthy individuals and stroke survivors control their footpath during walking. Furthermore, the footpath stabilization and gait parameters can be modified following gait training. However, clear evidence regarding the superiority of one training paradigm over other is lacking, therefore future studies are needed to identify efficient strategies for gait rehabilitation poststroke.