title: Gait Characteristics When Walking on Different Slippery Walkways.
abstract: OBJECTIVE
  This study sought to determine the changes in muscle activity about the ankle, knee, and hip in able-bodied people walking at steady state on surfaces with different degrees of slipperiness.
  
  
  METHODS
  Muscle activity was measured through electromyographic signals from selected lower limb muscles and quantified to directly compare changes across surface conditions.
  
  
  RESULTS
  Our results showed distinct changes in the patterns of muscle activity controlling each joint. Muscles controlling the ankle showed a significant reduction in activity as the surface became more slippery, presumably resulting in a compliant distal joint to facilitate full contact with the surface. Select muscles about the knee and hip showed a significant increase in activity as the surface became more slippery. This resulted in increased knee and hip flexion likely contributing to a lowering of the body's center of mass and stabilization of the proximal leg and trunk.
  
  
  CONCLUSIONS
  These findings suggest a proximal-distal gradient in the control of muscle activity that could inform the future design of adaptable prosthetic controllers.
  
  
  CONCLUSIONS
  Walking on a slippery surface is extremely difficult, especially for individuals with lower limb amputations because current prostheses do not allow the compensatory changes in lower limb dynamics that occur involuntarily in unimpaired subjects. With recent advances in prosthetic control, there is the potential to provide some of these compensatory changes; however, we first need to understand how able-bodied individuals modulate their gait under these challenging conditions.
authors.affiliation: Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
authors.forename: Mariah W
authors.initials: MW
authors.lastname: Whitmore
authors.affiliation: Department of Physical Medicine and RehabilitationNorthwestern University.
authors.forename: Levi J
authors.initials: LJ
authors.lastname: Hargrove
authors.affiliation: Departments of Biomedical Engineering and Physical Medicine and RehabilitationNorthwestern University.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Perreault
mesh_terms: D000328:Adult; D001186:Artificial Limbs; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D013499:Surface Properties; D016138:Walking / Q000502:physiology*; D055815:Young Adult