Oxygen uptake kinetics during two bouts of heavy cycling separated by fatiguing sprint exercise in humans - Université de Franche-Comté Access content directly
Journal Articles Journal of Applied Physiology Year : 2003

Oxygen uptake kinetics during two bouts of heavy cycling separated by fatiguing sprint exercise in humans

Abstract

We tested the hypothesis that O 2 uptake (V˙o 2 ) kinetics at the onset of heavy exercise would be altered in a state of muscle fatigue and prior metabolic acidosis. Eight well-trained cyclists completed two identical bouts of 6-min cycling exercise at >85% of peak V˙o 2 separated by three successive bouts of 30 s of sprint cycling. Not only was baselineV˙o 2 elevated after prior sprint exercises but also the time constant of phase IIV˙o 2 kinetics was faster (28.9 ± 2.4 vs. 22.2 ± 1.7 s; P < 0.05). CO 2 output (V˙co 2 ) was significantly reduced throughout the second exercise bout. SubsequentlyV˙o 2 was greater at 3 min and increased less after this after prior sprint exercise. Cardiac output, estimated by impedance cardiography, was significantly higher in the first 2 min of the second heavy exercise bout. Normalized integrated surface electromyography of four leg muscles and normalized mean power frequency were not different between exercise bouts.V˙o 2 andV˙co 2 kinetic responses to heavy exercise were markedly altered by prior multiple sprint exercises.
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Dates and versions

hal-03547725 , version 1 (28-01-2022)

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Nicolas Tordi, S. Perrey, A. Harvey, R. Hughson. Oxygen uptake kinetics during two bouts of heavy cycling separated by fatiguing sprint exercise in humans. Journal of Applied Physiology, 2003, 94 (2), pp.533-541. ⟨10.1152/japplphysiol.00532.2002⟩. ⟨hal-03547725⟩
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