title: Locomotor-Respiratory Coupling in Wheelchair Racing Athletes: A Pilot Study.
abstract: OBJECTIVE
  In wheelchair racing, respiratory muscles of the rib cage are concomitantly involved in non-ventilatory functions during wheelchair propulsion. However, the relationship between locomotor-respiratory coupling (LRC: the ratio between push and breathing frequency), respiratory parameters and work efficiency is unknown. Therefore, the aim of the present study was to investigate the LRC in wheelchair racers over different race distances.
  
  
  METHODS
  Eight trained and experienced wheelchair racers completed three time-trials over the distances of 400, 800, and 5000 m on a training roller in randomized order. During the time trials, ventilatory and gas exchange variables as well as push frequency were continuously registered to determine possible LRC strategies.
  
  
  RESULTS
  Four different coupling ratios were identified, namely 1:1; 2:1, 3:1 as well as a 1:1/2:1 alternating type, respectively. The 2:1 coupling was the most dominant type. The 1:1/2:1 alternating coupling type was found predominantly during the 400 m time-trial. Longer race distances tended to result in an increased coupling ratio (e.g., from 1:1 toward 2:1), and an increase in coupling ratio toward a more efficient respiration was found over the 5000 m distance. A significant correlation (r = 0.80, p < 0.05) between respiratory frequency and the respiratory equivalent for oxygen was found for the 400 m and the 800 m time-trials.
  
  
  CONCLUSIONS
  These findings suggest that a higher coupling ratio indicates enhanced breathing work efficiency with a concomitant deeper and slower respiration during wheelchair racing. Thus, the selection of an appropriate LRC strategy may help to optimize wheelchair racing performance.
authors: Institute of Sports Medicine, Swiss Paraplegic CentreNottwil, Switzerland; European Research Group in Disability Sport.
authors: Claudio
authors: C
authors: Perret
authors: Institute of Sport Science, Faculty of Human Sciences, University of Bern Bern, Switzerland.
authors: Martin
authors: M
authors: Wenger
authors: European Research Group in Disability Sport; The Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough UniversityLoughborough, UK.
authors: Christof A
authors: CA
authors: Leicht
authors: European Research Group in Disability Sport; The Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough UniversityLoughborough, UK.
authors: Victoria L
authors: VL
authors: Goosey-Tolfrey
keywords: elite sports; exercise; push frequency; respiratory muscles; spinal cord injury