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Br J Sports Med doi:10.1136/bjsm.2010.083071
  • Original article

Allometric scaling of peak power output accurately predicts time trial performance and maximal oxygen consumption in trained cyclists

  1. Timothy D Noakes
  1. UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, The Sport Science Institute of South Africa, Newlands, South Africa
  1. Correspondence to Dr Robert Patrick Lamberts, UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Sport Science Institute of South Africa, University of Cape Town, PO Box 115, Newlands 7725, South Africa; RPLam{at}hotmail.com
  • Accepted 29 June 2011
  • Published Online First 4 August 2011

Abstract

Objective The purpose of this study was to determine if peak power output (PPO) adjusted for body mass0.32 is able to accurately predict 40-km time trial (40-km TT) performance.

Methods 45 trained male cyclists completed after familiarisation, a PPO test including respiratory gas analysis, and a 40-km TT. PPO, maximal oxygen consumption (VO2max) and 40-km TT time were measured. Relationships between 40-km TT performance and (I) absolute PPO (W) and VO2max (l/min), (II) relative PPO (W/kg) and VO2max (ml/min/kg) and (III) PPO and VO2max adjusted for body mass (W/kg0.32 and ml/min/kg0.32, respectively) were studied.

Results The continuous ramp protocol resulted in a similar relationship between PPO and VO2max (r=0.96, p<0.0001) compared with a stepwise testing protocol but was associated with a lower standard error of the estimated when predicting VO2max. PPO adjusted for body mass (W/kg0.32) had the strongest relationship with 40-km TT performance (s) (r=−0.96, p<0.0001). Although significant relationships were also found between absolute (W) and/or relative PPO (W/kg) and 40-km TT performance (s), these relationships were significantly weaker than the relationship between 40-km TT performance and PPO adjusted for body mass (W/kg0.32) (p<0.0001).

Conclusions VO2max can be accurately predicted from PPO when using a continuous ramp protocol, possibly even more accurately than when using a stepwise testing protocol. 40-km TT performance (s) in trained cyclists can be predicted most accurately by PPO adjusted for body mass (W/kg0.32). As both VO2max and 40-km TT performance can be accurately predicted from a PPO test, this suggests that (well)-trained cyclists can possibly be monitored more frequently and with fewer tests.

Footnotes

  • Funding This study was funded by the RA Noakes Fellowship, Medical Research Council of South Africa, Discovery Health and the University of Cape Town.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval provided by the Research and Ethics Committee of the Faculty of Health Sciences of the University of Cape Town.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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