title: Effects of 4-weeks of asynchronous hand-rim wheelchair practice on mechanical efficiency and timing.
abstract: OBJECTIVE
  To investigate the consequence on gross mechanical efficiency (GE), arm frequency and sub-maximal performance, of paced and unpaced practice during asynchronous hand-rim wheelchair propulsion.
  
  
  METHODS
  Twenty-five able-bodied participants performed five, 4-min exercise bouts at 1.7 m/s, at the freely chosen frequency (FCF) and four paced arm frequencies of 60, 80, 120 and 140% FCF. GE, arm frequency and measures of sub-maximal performance were determined. Participants were assigned to an unpaced (FCF, N = 9), paced (80% FCF, N = 8) or control (CON, N = 8) no practice group. The FCF and 80% FCF groups received 4-weeks (unpaced and paced, respectively) propulsion practice (three sessions·per wk, four 4 min/trials; 33-35 W) at 1.7 m/s on a wheelchair ergometer. Following practice, the pre-testing protocol was repeated.
  
  
  RESULTS
  Mean GE showed a relative increase in both experimental groups (21 and 17%; FCF and 80% FCF respectively; p = 0.001) compared to no change in CON (-1.5%). The FCF arm frequency decreased in both experimental groups (p = 0.001), with larger changes evident following FCF practice.
  
  
  CONCLUSIONS
  Four weeks of unpaced or paced practice had a beneficial effect on GE. This improvement seems to be associated with a reduction in arm frequency.
authors: Peter Harrison Centre for Disability Sport, School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK. J.P.Lenton@lboro.ac.uk
authors: John Paul
authors: JP
authors: Lenton
authors: Lucas H V
authors: LH
authors: Van Der Woude
authors: Neil E
authors: NE
authors: Fowler
authors: Victoria
authors: V
authors: Goosey-Tolfrey
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000704:Analysis of Variance; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D016552:Ergometry; D005080:Exercise Test; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D009068:Movement / Q000502:physiology; D013647:Task Performance and Analysis; D014910:Wheelchairs; D055815:Young Adult