Muscle Activation Differs Between Individuals During Initial Powered Ankle Exoskeleton Adaptation

Abstract

Although previous studies have shown that powered exoskeletons reduce muscle activation while walking across participants, less is known about how they impact an individual’s muscle activation. This study examined an individual’s muscle activity during walking with a powered ankle exoskeleton. The designed human-exoskeleton coordination was defined as a decrease in medial gastrocnemius (MGAS) muscle activation with the exoskeleton powered and increase with the exoskeleton unpowered. 60% of the participants were observed to coordinate with the exoskeleton as designed, with 67% showing a decrease in RMS MGAS during adaptation. 60% of the participants showed no change during the de-adaptation, with 47% not returning to baseline metrics by late de-adaptation. Muscle activity differs between individuals in response to the exoskeleton power state and over time within the power state. It is important to consider these different behaviors when integrating exoskeletons into occupational settings as adaptation may be supported by training and experience.