title: Powered hip exoskeletons can reduce the user's hip and ankle muscle activations during walking.
abstract: In this paper, we study the human locomotor adaptation to the action of a powered exoskeleton providing assistive torque at the user's hip during walking. To this end, we propose a controller that provides the user's hip with a fraction of the nominal torque profile, adapted to the specific gait features of the user from Winter's reference data . The assistive controller has been implemented on the ALEX II exoskeleton and tested on ten healthy subjects. Experimental results show that when assisted by the exoskeleton, users can reduce the muscle effort compared to free walking. Despite providing assistance only to the hip joint, both hip and ankle muscles significantly reduced their activation, indicating a clear tradeoff between hip and ankle strategy to propel walking.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Lenzi
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Carrozza
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Agrawal
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000843:Ankle Joint; D011211:Electric Power Supplies; D004734:Energy Metabolism / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006621:Hip Joint; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009989:Orthotic Devices; D005082:Physical Exertion / Q000502:physiology; D012016:Reference Values; D012371:Robotics / Q000295:instrumentation*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*