Reduction of V̇O2 slow component by priming exercise: novel mechanistic insights from time-resolved near-infrared spectroscopy.
Reduction of V̇O2 slow component by priming exercise: novel mechanistic insights from time-resolved near-infrared spectroscopy.
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DOI：
10.14814/phy2.12432
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发表时间：
2015-06
影响因子：
2.5
通讯作者：
Koga S
中科院分区：
文献类型：
--
作者：
Fukuoka Y;Poole DC;Barstow TJ;Kondo N;Nishiwaki M;Okushima D;Koga S
采用新型时间分辨近红外光谱（TR-NIRS）和脂肪组织厚度校正来检验以下假设：重度预充运动通过升高股四头肌（2）内多个部位的微血管[Hb]体积（而不是降低肌肉脱氧动力学的异质性）来降低V <$O2慢成分（V <$O2SC）（1）。12名受试者完成了两次6分钟的重负荷运动，间隔6分钟的无负荷自行车。预充运动诱导了更快的总体V_（50）O_2动力学，结果是V_（50）O_2SC显著降低（0.27 ± 0.12 vs. 0.11 ± 0.09 L·min-1，P < 0.05），而初始V_（50）O_2时间常数不变。预激组[总（Hb + Mb）]的基线增加（197.5 ± 21.6 vs. 210.7 ± 22.5 μmol L-1，P < 0.01），反映微血管[Hb]体积增加，与V ~ O2 SC减少显著相关。在股四头肌内的多个部位，预激运动降低了基线，并减缓了[脱氧（Hb + Mb）]的增加。在第二回合的时间延迟和时间常数的[脱氧（Hb + Mb）]的变异系数的变化与V今O2 SC减少不相关。这些结果支持启动运动引起的肌肉[Hb]体积增加和用于加速总体V ~ O2动力学的V ~ O2 SC减少之间的机械联系。然而，肌肉脱氧动力学的异质性的减少似乎不是引发反应的强制性特征。
Novel time-resolved near-infrared spectroscopy (TR-NIRS), with adipose tissue thickness correction, was used to test the hypotheses that heavy priming exercise reduces the V̇O2 slow component (V̇O2SC) (1) by elevating microvascular [Hb] volume at multiple sites within the quadriceps femoris (2) rather than reducing the heterogeneity of muscle deoxygenation kinetics. Twelve subjects completed two 6-min bouts of heavy work rate exercise, separated by 6 min of unloaded cycling. Priming exercise induced faster overall V̇O2 kinetics consequent to a substantial reduction in the V̇O2SC (0.27 ± 0.12 vs. 0.11 ± 0.09 L·min−1, P < 0.05) with an unchanged primary V̇O2 time constant. An increased baseline for the primed bout [total (Hb + Mb)] (197.5 ± 21.6 vs. 210.7 ± 22.5 μmol L−1, P < 0.01), reflecting increased microvascular [Hb] volume, correlated significantly with the V̇O2SC reduction. At multiple sites within the quadriceps femoris, priming exercise reduced the baseline and slowed the increase in [deoxy (Hb + Mb)]. Changes in the intersite coefficient of variation in the time delay and time constant of [deoxy (Hb + Mb)] during the second bout were not correlated with the V̇O2SC reduction. These results support a mechanistic link between priming exercise-induced increase in muscle [Hb] volume and the reduced V̇O2SC that serves to speed overall V̇O2 kinetics. However, reduction in the heterogeneity of muscle deoxygenation kinetics does not appear to be an obligatory feature of the priming response.