Influence of priming exercise on pulmonary O2 uptake kinetics during transitions to high-intensity exercise at extreme pedal rates

Fred J. DiMenna, Daryl P. Wilkerson, Mark Burnley, Stephen J. Bailey, Andrew M. Jones

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

    18 Dyfyniadau (Scopus)

    Crynodeb

    We investigated the pedal rate dependency of the effect of priming exercise on pulmonary oxygen uptake (VO2) kinetics. Seven healthy men completed two, 6-min bouts of high-intensity cycle exercise (separated by 6 min of rest) using different combinations of extreme pedal rates for the priming and criterion exercise bouts (i.e., 35-35, 35-115, 115-35, and 115-115 rev/min). Pulmonary gas exchange and heart rate were measured breath-by-breath, and muscle oxygenation was assessed using near-infrared spectroscopy. When the priming bout was performed at 35 rev/min (35-35 and 35-115 conditions), the phase II VO2 time constant (tau) was not significantly altered (bout 1: 31 ± 7 vs. bout 2: 30 ± 5 s and bout 1: 48 ± 16 vs. bout 2: 46 ± 21 s, respectively). However, when the priming bout was performed at 115 rev/min (115-35 and 115-115 conditions), the phase II tau was significantly reduced (bout 1: 31 ± 7 vs. bout 2: 26 ± 5 s and bout 1: 48 ± 16 vs. bout 2: 39 ± 9 s, respectively, P <0.05). Muscle oxygenation was significantly higher after priming exercise in all four conditions, but significant effects on VO2 kinetics were only evident when muscle O2 extraction (measured as delta[deoxyhemoglobin]/delta VO2) was elevated in the fundamental response phase. These data indicate that prior high-intensity exercise at a high pedal rate can speed VO2 kinetics during subsequent high-intensity exercise, presumably through specific priming effects on type II muscle fibers.
    Iaith wreiddiolSaesneg
    Tudalennau (o-i)432-442
    Nifer y tudalennau11
    CyfnodolynJournal of Applied Physiology
    Cyfrol106
    Rhif cyhoeddi2
    StatwsCyhoeddwyd - Chwef 2009

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