title: Effect of walking velocity on segment coordination during pre-planned turns in healthy older adults.
abstract: BACKGROUND
  Despite the prevalence of turning in daily activities and the challenges it poses to mobility-impaired individuals, far less is known about the multi-segmental control of turning than the control of straight walking. Gait slows with aging and neurological disorders such as Parkinson's disease and falls in these populations frequently occur when turning. Nevertheless, the influence of walking velocity on the complex inter-segmental coordination of the head, trunk and lower limbs during turning has not been examined. The purpose of this study was to examine the effect of walking velocity on the coordination of segment reorientation during turns embedded in locomotion in healthy older adults.
  
  
  METHODS
  Nineteen healthy older adults volunteered to participate. Participants made a 45 degrees or 90 degrees turn to their right while walking either at their natural self-selected speed or slower or faster than their natural speed. We quantified the timing and sequence of segments reorientation during the turns.
  
  
  RESULTS
  There was a top-down temporal sequence in initiation of segments reorientation during turning, i.e., head turned first, followed by shoulder, pelvis, and mediolateral foot displacement. Furthermore, results indicate that the top-down temporal sequence in segments reorientation during turning was a robust behavior which was not affected by the walking velocity or magnitude of the turn.
  
  
  CONCLUSIONS
  Walking velocity does not affect segment coordination during pre-planned turns in healthy elderly. Therefore, we conclude that changes in coordination of segments reorientation during pre-planned turns in individuals with neurological disorders such as Parkinson's disease is not due to their slower gait.
authors.affiliation: Department of Kinesiology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada. sbakram@ahsmail.uwaterloo.ca
authors.forename: Sakineh B
authors.initials: SB
authors.lastname: Akram
authors.forename: James S
authors.initials: JS
authors.lastname: Frank
authors.forename: Julia
authors.initials: J
authors.lastname: Fraser
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology*; D012016:Reference Values; D016138:Walking / Q000502:physiology*