Characterizing Expert Exoskeleton-Assisted Gait: Insights to Accelerate Ankle Exoskeleton Mastery

Exoskeletons can make walking easier, but extensive training is needed to fully benefit from them, potentially hindering device adoption. Coaching new exoskeleton users to walk with energetically beneficial gait patterns might accelerate motor learning, but these target patterns have yet to be established. In this study, we characterized changes in gait biomechanics between healthy young adults first exposure to ankle exoskeletons and after 7+ hours of training when they demonstrated full motor adaptation. We observed consistent markers of adaptation in ankle kinematics and spatial gait features; expert exoskeleton users exhibited greater ankle dorsiflexion before a powerful and concentrated push-off while walking with narrower and longer steps. Adaptations in muscle coordination patterns were more varied, but generally involved reducing co-contraction throughout the leg. By the end of training, non-propulsive exoskeleton-assisted gait features approached those of unassisted walking. Our results suggest that effective exoskeleton use involves selectively avoiding most disruptions to typical gait while accommodating energetically beneficial changes around push-off. All reported gait features can be monitored and targeted in real-time, facilitating the application of these results to reduce the time burden for novice users to maximally benefit from ankle exoskeletons.