Entrainment of gait phase in healthy subjects during rhythmic electrical stimulation of the gastrocnemius

This study investigated whether the human gait cycle spontaneously entrains to rhythmic electrical stimulation of the gastrocnemius muscle with phasing that aligns the stimuli with ankle push-off. Rhythmic stimulation was applied at the natural stride frequency, with random initial phasing. Some, but not all, participants entrained their gait to the stimulus. In stable entrained trials, stimulus phase was near push-off in treadmill trials but not in overground trials. Prevalence of entrainment appeared related to stimulus amplitude. Rhythmic gastrocnemius stimulation shows promise as a means of manipulating gait when amplitude of stimulation is adequate.