Functional electrical stimulation of the plantar flexor muscles in addition to the dorsiflexors surprisingly had no effect on mechanical recovery during post-stroke gait in a study performed at the University of Delaware.
Researchers analyzed the effects of dorsiflexion FES alone and combined dorsiflexor and plantar flexor FES in eight chronic stroke subjects while walking on an instrumented treadmill at a self-selected speed. Each stimulation was 30 Hz and lasted 300 msec. Dorsiflexion stimulation was applied during the paretic limb swing phase; combination stimulation was applied during paretic limb terminal stance only.
Average mechanical recovery for the group was significantly higher during the dorsiflexion FES condition than when no FES was applied. The combination FES condition, however, was not significantly different from the no-FES condition.
The authors hypothesized that the timing of the combination FES may have led to an increase in knee flexion rather than the expected forward acceleration of the center of mass. The findings were presented in August at the annual meeting of the American Society of Biomechanics.