Lower limb muscle synergies during gait in humans

Muscle synergies were extracted using nonnegative matrix factorization from muscle activation patterns in six lower limb muscles during normal gait. Greater than 70% of the variance in the muscle activations was described by four extracted synergies and greater than 90% was described by five synergies. Considering the timing of synergy activation, the extracted synergies appear to be related to functional divisions of the gait cycle.