Assessing the Effect of a Powered Ankle Exoskeleton on Human Agility with Inertial Measurement Units

Human agility describes the capacity to quickly adjust body movements in response to the environment. This study quantifies agility through performance on 0º, 45º, 90º, and 180º turns on an outdoor agility course. Participants (n=17) walked the course while wearing an ankle exoskeleton in powered and unpowered states, and their own shoes before and after the exoskeleton trials. Agility was quantified using Inertial Measurement Units placed on the feet. All metrics varied significantly with turn type and exhibited larger effect sizes than with changes in condition. Stride duration moderately increased in both exoskeleton conditions on 0º, 45º, and 90º turns. On 180º turns, the unpowered exoskeleton moderately decreased radial acceleration while the powered exoskeleton moderately increased speed and tangential acceleration. The results suggest that the evaluated ankle exoskeleton would be unobtrusive for similar healthy young users in their daily environments. The methods propose a framework for further study of exoskeletons and agility in a broader set of users with additional exoskeleton systems.