Oxygen uptake kinetics during supra V·O 2max treadmill running in humans

Helen Carter, J. Pringle, T.J. Barstow, Jonathan Doust

Research output: Contribution to journalArticle

Abstract

Accurate classification of VO2 kinetics is essential to correctly interpret its control mechanisms. The purpose of this study was to examine VO2 kinetics in severe and supra-maximal intensity running exercise using two modelling techniques. Nine subjects (mean +/- S.D: age, 27 +/- 7 years; mass, 69.8 +/- 9.0 kg; VO2max, 59.1 +/- 1.8 mL x kg x min(-1)) performed a series of "square-wave" exercise transitions to exhaustion at running speeds equivalent to 80% of the difference between the VO2 at LT and VO2max (delta), and at 100%, 110% and 120% VO2max. The VO2 response was modelled with an exponential model and with a semi-logarithmic transformation, the latter assuming a certain steady state VO2. With the exponential model there was a significant reduction in the "gain" of the primary component in supra-maximal exercise (167 +/- 5 mL x kg(-1) x km(-1) at 80% delta to 142 +/- 5 mL x kg(-1) x km(-1) at 120% VO2max, p = 0.005). The time constant of the primary component also reduced significantly with increasing intensity (17.8 +/- 1.1 s at 80% delta to 12.5 +/- 1.2 s at 120% VO2max, p < 0.05). However, in contrast, using the semi-log model, the time constant significantly increased with intensity (30.9 +/- 13.5 s at 80% delta to 72.2 +/- 23.9 s at 120% VO2max, p < 0.05). Not withstanding the need for careful interpretation of mathematically modelled data, these results demonstrate that neither the gain nor the time constant of the VO2 primary component during treadmill running are invariant across the severe and supra-maximal exercise intensity domains when fit with an exponential model. This suggests the need for a reappraisal of the VO2/work rate relationship in running exercise.
Original languageEnglish
Pages (from-to)149-157
Number of pages9
JournalInternational Journal of Sports Medicine
Volume27
Issue number2
DOIs
Publication statusPublished - 28 Feb 2006

Keywords

  • Oxygen uptake kinetics
  • vo2max
  • training
  • sport and exercise science
  • human vo2 kinetics
  • sport science

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