Predicting the effect of unilaterally reducing the number of muscle synergies on gait

When walking function is impaired post-stroke, the number of paretic leg muscle synergies is often reduced. However, it is unknown whether this reduction is the primary cause of impairment. In this study, we used direct collocation optimal control to generate two walking predictions using a reduced number of paretic leg muscle synergies in a subject post-stroke. Our results show that a reduced number of paretic leg synergies need not cause impaired walking but could cause it if construction of the lower-dimensional synergies is constrained to be consistent with experimental observations.