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Int J Sports Med 1983; 04(1): 31-39
DOI: 10.1055/s-2008-1026013
© Georg Thieme Verlag Stuttgart · New York

Delayed Kinetics of V̇O2 in the Transition from Prior Exercise. Evidence for O2 Transport Limitation of V̇O2 Kinetics: A Review*

R. L. Hughson, M. A. Morrissey**
  • Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3GI
* Supported by Natural Sciences and Engineering Research Council, Canada.** Recipient of Natural Science and Engineering Research Council Graduate Scholarship.
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Publication Date:
14 March 2008 (online)

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Abstract

The influence of prior exercise state on the kinetics of V̇O2, V̇E, and HR was studied in six subjects. The exercise conditions tested were square wave increases in work rate from rest to 80% of the work rate at anaerobic threshold (AT), from O W loadless pedaling to 80% AT, from rest to 40% AT, and from 40% to 80% AT. The kinetic response was evaluated by the time constant (τ) and mean response time (MRT = time to achive 63% response) as determined by nonlinear regression. For both V̇O2 and HR, τ and MRT were not significantly different in the rest or O W to 80% AT tests, but were significantly faster in the rest to 40% AT test and significantly slower in the 40% to 80% AT test than the rest and O W to 80% AT tests. The τ for V̇E was significantly slower in the 40% to 80% AT tests than in the other tests. The coincident variation of HR and V̇O2 kinetics is taken as support for the hypothesis that V̇O2 kinetics are controlled by oxygen transport. Evidence from the literature that supports both the oxygen transport and the oxygen utilization for the control of V̇O2 kinetics is reviewed.

Key words

oxygen uptake - exercise - heart rate - ventilation - vasodilatation - muscle blood flow - muscle metabolism

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