Pulmonary O₂ uptake on-kinetics in sprint- and endurance-trained athletes

摘要

Pulmonary O₂ uptake kinetics during “step” exercise have not been characterized in young, sprint-trained (SPT), athletes. Therefore, the objective of this study was to test the hypotheses that SPT athletes would have (i) slower phase II kinetics and (ii) a greater oxygen uptake “slow component” when compared with endurance-trained (ENT) athletes. Eight sub-elite SPT athletes (mean (± SD) age = 25 (±7) y; mass = 80.3 (±7.3) kg) and 8 sub-elite ENT athletes (age= 28 (±4) y; mass = 73.2 (±5.1) kg) completed a ramp incremental cycle ergometer test, a Wingate 30 s anaerobic sprint test, and repeat “step” transitions in work rate from 20 W to moderate- and severe-intensity cycle exercise, during which pulmonary oxygen uptake was measured breath by breath. The phase II oxygen uptake kinetics were significantly slower in the SPT athletes both for moderate (time constant, τ; SPT 32 (±4) s vs. ENT 17 (±3) s; p< 0.01) and severe (SPT 32 (±12) s vs. ENT 20 (±6) s; p< 0.05) exercise. The amplitude of the slow component (derived by exponential modelling) was not significantly different between the groups (SPT 0.55 (±0.12) L·min-1 vs. ENT 0.50 (±0.22) L·min-1), but the increase in oxygen uptake between 3 and 6min of severe exercise was greater in the SPT athletes (SPT 0.37 (±0.08) L·min-1 vs. ENT 0.20 (±0.09) L·min-1; p< 0.01). The phase II τ was significantly correlated with indices of aerobic exercise performance (e.g., peak oxygen uptake (moderate-intensity r =-0.88, p< 0.01; severe intensity r =-0.62; p< 0.05), whereas the relative amplitude of the oxygen uptake slow component was significantly correlated with indices of anaerobic exercise performance (e.g., Wingate peak power output; r = 0.77; p< 0.01). Thus, it could be concluded that sub-elite SPT athletes have slower phase II oxygen uptake kinetics and a larger oxygen uptake slow component compared with sub-elite ENT athletes. It appears that indices of aerobic and anaerobic exercise performance differentially influence the fundamental and slow components of the oxygen uptake kinetics.La cinétique de la consommation d'oxygène n'a pas encore fait l'objet d'étude chez de jeunes athlètes entraînés au sprint (SPT). La présente étude se propose donc de vérifier l'hypothèse selon laquelle les athlètes SPT passent par une phase II plus lente en ce qui concerne la cinétique de la consommation d'oxygène et que son ampleur dépasse celle des individus entraînés à l'endurance (ENT). Huit sujets SPT presque rendus au niveau élite (moyenne (± é-t) âge 25 (± 7) ans; masse 80,3 (±7,3) kg) et 8 sujets ENT (âge 28 (± 4) ans; masse 73,2 (± 5,1) kg) également presque rendus au niveau élite participent à un test d'effort progressif sur ergocycle, soit l'épreuve de Wingate d'une durée de 30 s et à une séance répétée de transition brusque de palier depuis une intensité de travail égale à 20W jusqu'à une intensité de travail modéré et très intense; durant ces exercices de transition, on évalue la consommation d'oxygène à chaque respiration.