Feasibility of Wearable Haptic Biofeedback Training for Reducing the Knee Abduction Moment During Overground Walking.

Gait modifications are effective in reducing the first peak knee abduction moment (PKAM), a surrogate for knee loading. Reliance on 3D motion capture currently restricts these modifications to the laboratory. Therefore, our purpose was to test the feasibility of a novel wearable biofeedback system to train (1) toe-in and trunk lean modifications and (2) combined toe-in and trunk lean modifications to reduce PKAM during overground walking outside of the laboratory. Twelve healthy participants practiced modifications in a university hallway directly after performing five normal walking trials. The wearable feedback system provided real-time haptic biofeedback during training trials to inform participants if they were within the prescribed modification range (7-12 deg greater than baseline). Participants were instructed to move to the next modification only once they felt comfortable and could perform it with minimal errors. Following training, five trials of each modification were immediately performed in the gait laboratory without feedback. All participants successfully modified their foot progression and trunk angle using the wearable system. At post-test, PKAM decreased from baseline by 62%, 55%, and 28% during combined, trunk leanand toe-in gait, respectively. The wearable feedback system was effective to modify participants' foot and trunk angle by the prescribed amount, resulting in reduced PKAM during all modifications at post-test. Participants were also able to perform a combined modification, although it took longer to report feeling comfortable doing so. This study demonstrates that a wearable feedback system is feasible to modify kinematic parameters and train gait modifications outside the laboratory.