title: Wheeling efficiency: the effects of varying tyre pressure with children and adolescents.
abstract: OBJECTIVE
  Clinicians often observe child wheelchair users wheeling on tyres that are not inflated to manufacturer's recommendations. The purpose of this study was to investigate changes in energy expenditure that are related to decreased tyre pressure.
  
  
  METHODS
  A within subject repeated measures design was used to assess the energy requirements of wheeling with four randomized tire inflation levels (25, 50, 75 and 100% of recommended tire pressure, 100 psi). All 10 subjects (mean age 14.2 +/- 2.3 years completed four 5-minute trials (one for each tyre pressure), while wheeling at a constant, self-selected velocity. Heart rate and wheeling velocity were measured.
  
  
  RESULTS
  There was no change in wheeling velocity with changes in tyre pressure; however, energy expenditure was found to increase by over 15% with decreasing tyre pressure (p < 0.05).
  
  
  CONCLUSIONS
  In order for children to minimize their energy expenditure and, thus, improve their independence, clinicians and parents must be educated as to the importance of regular wheelchair tyre inflation regimes.
authors.affiliation: Department of Orthopaedics, University of British Columbia, Vancouver, Canada. bsawatzky@cw.bc.ca
authors.forename: Bonita J
authors.initials: BJ
authors.lastname: Sawatzky
authors.forename: Ian
authors.initials: I
authors.lastname: Denison
mesh_terms: D000293:Adolescent; D000399:Air Pressure; D002648:Child; D004734:Energy Metabolism; D004867:Equipment Design; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D014910:Wheelchairs