title: An approach to estimating gross efficiency during high-intensity exercise.
abstract: OBJECTIVE
  Gross efficiency (GE) is coupling power production to propulsion and is an important performance-determining factor in endurance sports. Measuring GE normally requires measuring VO(2) during submaximal exercise. In this study a method is proposed to estimating GE during high-intensity exercise.
  
  
  METHODS
  Nineteen subjects completed a maximal incremental test and 2 GE tests (1 experimental and 1 control test). The GE test consisted of 10 min cycling at 50% peak power output (PPO), 2 min at 25 W, followed by 4 min 100% PPO, 1 min at 25 W, and another 10 min at 50% PPO. GE was determined for the 50%-PPO sections and was, for the second 50%-PPO section, back-extrapolated, using linear regression, to the end of the 100%-PPO bout.
  
  
  RESULTS
  Back-extrapolation of the GE data resulted in a calculated GE of 15.8% ± 1.7% at the end of the 100%-PPO bout, in contrast to 18.3% ± 1.3% during the final 2 min of the first 10-min 50%-PPO bout.
  
  
  CONCLUSIONS
  Back-extrapolation seems valuable in providing more insight in GE during high-intensity exercise.
authors.affiliation: Research Inst MOVE, VU-University, Amsterdam, The Netherlands.
authors.forename: Jos J
authors.initials: JJ
authors.lastname: de Koning
authors.forename: Dionne A
authors.initials: DA
authors.lastname: Noordhof
authors.forename: Tom P
authors.initials: TP
authors.lastname: Uitslag
authors.forename: Rianna E
authors.initials: RE
authors.lastname: Galiart
authors.forename: Christopher
authors.initials: C
authors.lastname: Dodge
authors.forename: Carl
authors.initials: C
authors.lastname: Foster
mesh_terms: D016552:Ergometry / Q000379:methods; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology