Gradually learning to increase gait propulsion in young unimpaired adults

Distorted visual feedback (DVF) may employ both implicit and explicit approaches to enhance motor learning. Our purpose was to test the effect of DVF of gait propulsion on the capacity to alter propulsive forces, and to determine the biomechanical determinants of propulsion. Seventeen young unimpaired individuals walked for three minutes of baseline (no feedback), then completed three randomly ordered, 10-minute Learning conditions: Real, 10DVF, and 20DVF. During the DVF conditions, we gradually decreased the feedback value without the participants' knowledge. For all Learning conditions, participants were instructed to maintain the propulsive force between two targets representing ±1 standard deviation as obtained from baseline. A one-minute retention trial without any feedback was performed immediately after Learning. Participants increased propulsive forces and trailing limb angle in both DVF conditions that persisted through retention; however, no change in ankle plantarflexion moment was noted. These findings offer promise of translation to clinical populations with propulsion deficits and require combined implicit and explicit learning components.