Priming exercise speeds pulmonary O2 uptake kinetics during supine "work-to-work" high-intensity cycle exercise
Priming exercise speeds pulmonary O2 uptake kinetics during supine "work-to-work" high-intensity cycle exercise
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DOI：
10.1152/japplphysiol.01047.2009
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发表时间：
2010-02-01
影响因子：
3.3
通讯作者：
Jones, Andrew M.
中科院分区：
文献类型：
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作者：
DiMenna, Fred J.;Wilkerson, Daryl P.;Jones, Andrew M.
DiMenna FJ，Wilkerson DP，Burnley M，Bailey SJ，Jones AM.在仰卧“工作到工作”的高强度循环运动中，预充运动加速了肺氧摄取动力学。J Appl Physiol 108：283-292，2010.首次发表于2009年12月3日; doi：10.1152/japplphysiol.01047.2009。我们操纵基线代谢率和体位，以探讨在周期运动期间肌纤维池离散部分的募集和肌肉O-2输送对肺O-2摄取（Vo（2））动力学的相互作用。我们假设，由于肌肉灌注受损，从中等强度运动到严重强度运动的II相Vo（2）动力学（T-p）在仰卧位比直立位明显慢，并且严重强度运动的启动回合将使仰卧运动期间的T-p恢复到直立运动期间的T-p。8名男性受试者[35 +/- 13（SD）岁]完成了一系列从“无负荷”（20 W）基线到仰卧和直立体位中等强度运动基线的“阶梯”过渡到重度强度周期运动。在从20 W基线到中等或严重强度运动的过渡期间，仰卧位和直立位运动之间的T-p没有显著差异，但在仰卧位的中等至严重强度运动期间，T-p显著更大（54 +/- 19 vs. 38 +/- 10 s，P < 0.05）。在中度至重度仰卧运动（34 +/- 9 s）期间，预激显著降低了T-p，使其恢复到与直立位T-p无显著差异的值。这种效应发生在估计的肌肉O-2提取分数（来自近红外光谱衍生的脱氧Hb浓度信号）没有变化的情况下，因此引发诱导的肌肉血流促进与招募的纤维中O-2利用率增加相匹配，导致Vo（2）动力学加速。这些发现表明，在仰卧自行车期间，预充通过为高阶O-2扩散提供增加的驱动压力（即，II型）纤维，这将在从中等强度到严重强度运动的过渡中被招募，并且已知对O-2供应的限制特别敏感。
DiMenna FJ, Wilkerson DP, Burnley M, Bailey SJ, Jones AM. Priming exercise speeds pulmonary O-2 uptake kinetics during supine "work-to-work" high-intensity cycle exercise. J Appl Physiol 108: 283-292, 2010. First published December 3, 2009; doi:10.1152/japplphysiol.01047.2009.-We manipulated the baseline metabolic rate and body position to explore the effect of the interaction between recruitment of discrete sections of the muscle fiber pool and muscle O-2 delivery on pulmonary O-2 uptake (Vo(2)) kinetics during cycle exercise. We hypothesized that phase II Vo(2) kinetics (T-p) in the transition from moderate- to severe-intensity exercise would be significantly slower in the supine than upright position because of a compromise to muscle perfusion and that a priming bout of severe-intensity exercise would return T-p during supine exercise to T-p during upright exercise. Eight male subjects [35 +/- 13 (SD) yr] completed a series of "step" transitions to severe-intensity cycle exercise from an "unloaded" (20-W) baseline and a baseline of moderate-intensity exercise in the supine and upright body positions. T-p was not significantly different between supine and upright exercise during transitions from a 20-W baseline to moderateor severe-intensity exercise but was significantly greater during moderate- to severe-intensity exercise in the supine position (54 +/- 19 vs. 38 +/- 10 s, P < 0.05). Priming significantly reduced T-p during moderate- to severe-intensity supine exercise (34 +/- 9 s), returning it to a value that was not significantly different from T-p in the upright position. This effect occurred in the absence of changes in estimated muscle fractional O-2 extraction (from the near-infrared spectroscopy-derived deoxygenated Hb concentration signal), such that the priming-induced facilitation of muscle blood flow matched increased O-2 utilization in the recruited fibers, resulting in a speeding of Vo(2) kinetics. These findings suggest that, during supine cycling, priming speeds Vo(2) kinetics by providing an increased driving pressure for O-2 diffusion in the higher-order (i.e., type II) fibers, which would be recruited in the transition from moderate- to severe-intensity exercise and are known to be especially sensitive to limitations in O-2 supply.