title: Interlimb coordination in body-weight supported locomotion: A pilot study.
abstract: Locomotion involves complex neural networks responsible for automatic and volitional actions. During locomotion, motor strategies can rapidly compensate for any obstruction or perturbation that could interfere with forward progression. In this pilot study, we examined the contribution of interlimb pathways for evoking muscle activation patterns in the contralateral limb when a unilateral perturbation was applied and in the case where body weight was externally supported. In particular, the latency of neuromuscular responses was measured, while the stimulus to afferent feedback was limited. The pilot experiment was conducted with six healthy young subjects. It employed the MIT-Skywalker (beta-prototype), a novel device intended for gait therapy. Subjects were asked to walk on the split-belt treadmill, while a fast unilateral perturbation was applied mid-stance by unexpectedly lowering one side of the split-treadmill walking surfaces. Subject's weight was externally supported via the body-weight support system consisting of an underneath bicycle seat and the torso was stabilized via a loosely fitted chest harness. Both the weight support and the chest harness limited the afferent feedback. The unilateral perturbations evoked changes in the electromyographic activity of the non-perturbed contralateral leg. The latency of all muscle responses exceeded 100ms, which precludes the conjecture that spinal cord alone is responsible for the perturbation response. It suggests the role of supraspinal or midbrain level pathways at the inter-leg coordination during gait.
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, 3-137 Cambridge, MA 02139, USA; Department of Mechanical and Process Engineering, ETH Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Seiterle
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, 3-137 Cambridge, MA 02139, USA.
authors.forename: Tyler
authors.initials: T
authors.lastname: Susko
authors.affiliation: Department of Matter, Transport and Energy, Arizona State University, USA.
authors.forename: Panagiotis K
authors.initials: PK
authors.lastname: Artemiadis
authors.affiliation: Department of Health Sciences and Technology, ETH Zurich, Switzerland; Faculty of Medicine, University of Zurich, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Riener
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, 3-137 Cambridge, MA 02139, USA; Department Neurology and Division Rehabilitative Medicine, University of Maryland, School of Medicine, USA; Department of Physical Medicine and Rehabilitation, Fujita Health University, Japan; Institute of Neuroscience, University of Newcastle, UK. Electronic address: hikrebs@mit.edu.
authors.forename: Hermano
authors.initials: H
authors.lastname: Igo Krebs
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D001835:Body Weight; D004576:Electromyography; D056228:Feedback, Sensory; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D009048:Motor Skills; D010865:Pilot Projects; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Gait; Gait perturbation; Interlimb coordination; Locomotion; Robotics; Training