title: The constant work rate critical power protocol overestimates ramp incremental exercise performance.
abstract: OBJECTIVE
  The parameters of the power-duration relationship (i.e., the critical power, CP, and the curvature constant, W') may theoretically predict maximal performance capability for exercise above the CP. The CP and W' are associated with the parameters of oxygen uptake ([Formula: see text]O2) kinetics, which can be altered by manipulation of the work-rate forcing function. We tested the hypothesis that the CP and W' derived from constant work-rate (CWR) prediction trials would overestimate ramp incremental exercise performance.
  
  
  METHODS
  Thirty subjects (males, n = 28; females, n = 2) performed a ramp incremental test, and 3-5 CWR prediction trials for the determination of the CP and W'. Multiple ramp incremental tests and corresponding CP and W' estimates were available for some subjects such that in total 51 ramp test performances were predicted.
  
  
  RESULTS
  The ramp incremental test performance (729 ± 113 s) was overestimated by the CP and W' estimates derived from the best (751 ± 114 s, P < 0.05) and worst (749 ± 111 s, P < 0.05) individual fits of CWR prediction trial data. The error in the prediction was inversely correlated with the magnitude of the W' for the best (r = -0.56, P < 0.05) and worst individual fits (r = -0.36, P < 0.05).
  
  
  CONCLUSIONS
  The overestimation of ramp incremental performance suggests that the CP and W' derived from different work-rate forcing functions, thus resulting in different [Formula: see text]O2kinetics, cannot be used interchangeably. The present findings highlight a potential source of error in performance prediction that is of importance to both researchers and applied practitioners.
authors: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK.|School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, LE11 3TU, UK.
authors: Matthew I
authors: MI
authors: Black
authors: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK.
authors: Andrew M
authors: AM
authors: Jones
authors: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK.
authors: James A
authors: JA
authors: Kelly
authors: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK.|School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, LE11 3TU, UK.
authors: Stephen J
authors: SJ
authors: Bailey
authors: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK. a.vanhatalo@exeter.ac.uk.
authors: Anni
authors: A
authors: Vanhatalo
mesh_terms: D000328:Adult; D000465:Algorithms; D003198:Computer Simulation; D005080:Exercise Test / Q000379:methods*; D005260:Female; D000072696:High-Intensity Interval Training / Q000379:methods*; D006801:Humans; D008297:Male; D008954:Models, Biological; D053580:Muscle Strength; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013647:Task Performance and Analysis
keywords: Critical power; Performance prediction; Power-duration relationship; W′