%0 Journal Article %T Oxygen uptake kinetics during two bouts of heavy cycling separated by fatiguing sprint exercise in humans %+ Marqueurs pronostiques et facteurs de régulations des pathologies cardiaques et vasculaires - UFC ( UR 3920) (PCVP / CARDIO) %+ Pathologies et épithéliums : prévention, innovation, traitements, évaluation (EA 4267) (PEPITE) %+ Pathologies et épithéliums : prévention, innovation, traitements, évaluation (UR 4267) (PEPITE) %+ Fonctions et dysfonctions épithéliales - UFC (EA 4267) (FDE) %+ Centre de résonance magnétique biologique et médicale (CRMBM) %A Tordi, Nicolas %A Perrey, S. %A Harvey, A. %A Hughson, R. %< avec comité de lecture %@ 8750-7587 %J Journal of Applied Physiology %I American Physiological Society %V 94 %N 2 %P 533-541 %8 2003-02-01 %D 2003 %R 10.1152/japplphysiol.00532.2002 %Z Life Sciences [q-bio]Journal articles %X 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. %G English %L hal-03547725 %U https://univ-fcomte.hal.science/hal-03547725 %~ CNRS %~ UNIV-AMU %~ UNIV-FCOMTE %~ CRMBM