Haptic Feedback Increases Plantarflexion and Propulsion

Increasing forward propulsion is a common goal of gait rehabilitation after stroke, but not all individuals demonstrate improved function after rehabilitation. Haptic, or vibrotactile, feedback has been used to promote improvements in spatiotemporal gait biomechanics in unimpaired and clinical populations, but there is limited research on the use of haptic feedback to promote increased forward propulsion in either unimpaired individuals or individuals with chronic stroke. The purpose of this study was to determine if haptic feedback could be used to increase ankle plantarflexion and, by extension, forward propulsion in unimpaired individuals. Thirty-two unimpaired individuals completed two overground walking trials while wearing five inertial measurement units to calculate real-time joint angles and deliver haptic feedback. In the baseline trial, subjects were instructed to walk normally, and no feedback was delivered. In the feedback trial, haptic feedback was given when the subject's plantarflexion angle exceeded 10% more than the peak plantarflexion angle from the baseline trial. Peak ankle plantarflexion and anterior ground reaction force were compared between trials using a paired t-test (α = 0.05) and increased statistically significantly between trials (both p < 0.001). Individuals were able to interpret haptic feedback and change their gait accordingly, resulting in substantial increases in plantarflexion and propulsion. These results suggest that haptic feedback on plantarflexion angle may be a simple and effective way to increase forward propulsion in a poststroke population, although future research is needed to confirm these results in individuals with chronic stroke.