High muscle blood flow in man: is maximal O2 extraction compromised?
High muscle blood flow in man: is maximal O2 extraction compromised?
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人体肌肉血流量高：最大摄氧量是否受到影响？
DOI：
10.1152/jappl.1993.75.4.1911
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Wagner,PD
中科院分区：
文献类型：
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作者：
Richardson,RS;Poole,DC;Knight,DR;Kurdak,SS;Hogan,MC;Grassi,B;Johnson,EC;Kendrick,KF;Erickson,BK;Wagner,PD
在传统的自行车测功过程中，随着工作率 (WR) 增加到最大值，氧气提取量呈双曲线增加，通常在氧气吸收峰值 (VO2) 时达到 80-90% 的值。相比之下，使用孤立的膝伸肌运动的研究报告了更高的质量特异性血流量 (Q) 和更低的最大 O2 提取量（约 70%），这被解释为 O2 运动离开肌肉毛细血管的传输时间限制。然而，在常规自行车测功期间，通常在 WR 快速增加后达到（超过 10-15 分钟）可达到的最大 WR 水平，而报道的膝伸肌研究仅使用了更长的方案（45 分钟）。这些方案的持续时间可能阻碍了高 WR 水平的实现，从而阻碍了高 O2 提取率的实现。因此，这项研究检查了单腿膝伸肌运动快速增加时腿部 Q 和 O2 提取反应（每 2 至 3 分钟间隔 15-25 W），这会在 13-15 分钟内产生疲劳。 Q 和肌肉 VO2 随 WR 线性增加至疲劳，Q-WR 和 VO2-WR 斜率与之前的膝伸肌研究报告的相似。然而，通过使用该协议，获得了非常高的最大可实现 WR [99 +/- 6 (SE) W] 和肌肉 Q (385 +/- 26 ml.min-1 x 100 g-1) 水平，比之前报道的高约 80%。氧气提取率达到 84.6 +/- 2.1%，最大摄氧量为 60.2 +/- 5.8 ml.min-1 x 100 g-1。我们的结论是，即使在单腿膝伸肌运动的高 Q 条件下，O2 提取也不会因为短传输时间而达到稳定状态，并且之前的结论恰恰相反，反映出未能达到足够高的 WR 水平。该模型中的最大 VO2、Q 和 O2 提取量尚未定义。
During conventional cycle ergometry, as work rate (WR) is increased toward maximum, O2 extraction increases hyperbolically, typically achieving values of 80–90% at peak O2 uptake (VO2). In contrast, studies using isolated knee-extensor exercise report much higher mass-specific blood flows (Q) and lower maximal O2 extractions (approximately 70%), which have been interpreted as transit time limitation to O2 movement out of the muscle capillary. However, maximal achievable WR levels during conventional cycle ergometry are generally reached (over 10–15 min) after rapid increases in WR, whereas the reported knee-extensor studies have used only more lengthy protocols (45 min). The duration of these protocols may have prevented the attainment of high WR levels and thus high O2 extraction ratios. Accordingly, this investigation examined leg Q and O2 extraction responses during single-leg knee-extensor exercise incremented rapidly (steps of 15–25 W per 2- to 3-min interval), which produced fatigue in 13–15 min. Q and muscle VO2 increased linearly with WR to fatigue with Q-WR and VO2-WR slopes similar to those reported in previous knee-extensor studies. However, with the use of this protocol, very high maximal achievable WR [99 +/- 6 (SE) W] and muscle Q (385 +/- 26 ml.min-1 x 100 g-1) levels were attained, some 80% greater than previously reported. An O2 extraction of 84.6 +/- 2.1% was reached, giving a maximal VO2 of 60.2 +/- 5.8 ml.min-1 x 100 g-1. We conclude that, even under the high Q conditions of single-leg knee-extensor exercise, O2 extraction does not reach a plateau on the basis of short transit times and that previous conclusions to the contrary reflect failure to attain sufficiently high WR levels. Maximal VO2, Q, and O2 extraction in this model have yet to be defined.