Muscle contraction duration and fibre recruitment influence blood flow and oxygen consumption independent of contractile work during steady-state exercise in humans.
Muscle contraction duration and fibre recruitment influence blood flow and oxygen consumption independent of contractile work during steady-state exercise in humans.
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DOI：
10.1113/expphysiol.2011.062968
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发表时间：
2012-06
影响因子：
2.7
通讯作者：
Dinenno FA
中科院分区：
文献类型：
--
作者：
Richards JC;Crecelius AR;Kirby BS;Larson DG;Dinenno FA
我们测试了这样一个假设，即在匹配收缩工作的条件下，更短的收缩持续时间和更多的肌纤维补充会导致人类在稳态运动中骨骼肌血流量和耗氧量（V / O2）的增加。为此，我们测量了24名健康年轻人在4分钟有节奏的握力运动期间的前臂血流量（FBF；多普勒超声），并通过将导管逆行置入前臂肌肉深静脉中获得的血液样本计算了前臂V / O2。在方案1 （n = 11）中，受试者在保持张力时间指数（TTI；等距模拟工作）不变但控制收缩持续时间的条件下，以轻度和中度强度进行有节奏的等距握力锻炼。在这项研究中，在轻度负荷中，较短的收缩持续时间导致更大的FBF（184±25比164±25 ml·min-1）和V (O2)(23±3比17±2 ml·min-1， P均<0.05)，而在中等强度运动中则不是这样。在方案2 （n = 13）中，受试者在匹配的总工作量条件下进行轻度和中度强度的有节奏的动态握力锻炼，但控制肌纤维的补充。在该方案中，在轻度工作负荷下，肌肉纤维的增加显著增加了FBF（152±15 vs 127±13 ml·min-1）和V (O2)(20±2 vs 17±2 ml·min-1， P均<0.05)，在中等强度下也有类似的反应趋势，但这没有统计学意义。在两种方案中，在所有运动强度和操作中，FBF变化与V / O2变化的比例相似，所有变量中V / O2与血流之间的相关性最强。我们的集体数据表明，在匹配的工作量中，在轻度强度前臂运动中，较短的收缩持续时间和较大的肌纤维补充增加了FBF和V / O2，并且在人类稳态运动中，肌肉血流量与代谢成本（V / O2）而不是收缩功本身更密切相关。
We tested the hypothesis that, among conditions of matched contractile work, shorter contraction durations and greater muscle fibre recruitment result in augmented skeletal muscle blood flow and oxygen consumption (V̇O2) during steady-state exercise in humans. To do so, we measured forearm blood flow (FBF; Doppler ultrasound) during 4 minutes of rhythmic handgrip exercise in 24 healthy young adults and calculated forearm V̇O2 via blood samples obtained from a catheter placed in retrograde fashion into a deep vein draining the forearm muscle. In Protocol 1 (n = 11), subjects performed rhythmic isometric handgrip exercise at mild and moderate intensities under conditions in which tension time index (TTI; isometric analog of work) was held constant but contraction duration was manipulated. In this protocol, shorter contraction durations led to greater FBF (184 ± 25 vs. 164 ± 25 ml·min-1) and V̇O2 (23 ± 3 vs. 17 ± 2 ml·min-1; both P <0.05) among mild workloads, whereas this was not the case for moderate intensity exercise. In Protocol 2 (n = 13), subjects performed rhythmic dynamic handgrip exercise at mild and moderate intensities under conditions of matched total work, but muscle fibre recruitment was manipulated. In this protocol, greater muscle fibre recruitment led to significantly greater FBF (152 ± 15 vs. 127 ±13 ml·min-1) and V̇O2 (20 ± 2 vs. 17 ± 2 ml·min-1; both P<0.05) at mild workloads and there was a trend for similar responses at the moderate intensity but this was not statistically significant. In both protocols, the ratio of the change in FBF to change in V̇O2 was similar across all exercise intensities and manipulations, and the strongest correlation among all variables was between V̇O2 and blood flow. Our collective data indicate that, among matched workloads, shorter contraction duration and greater muscle fibre recruitment augment FBF and V̇O2 during mild intensity forearm exercise, and that muscle blood flow is more closely related to metabolic cost (V̇O2) rather than contractile work per se during steady-state exercise in humans.
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影响因子：
3.3
作者：
ADAMS, GR;DUVOISIN, MR;DUDLEY, GA
通讯作者：
DUDLEY, GA
影响因子：
3.3
作者：
CORCONDILAS, A;SHEPHERD, JT;KOROXENIDIS, GT
通讯作者：
KOROXENIDIS, GT
影响因子：
3.3
作者：
Naik, JS;Valic, Z;Clifford, PS
通讯作者：
Clifford, PS
影响因子：
5.5
作者：
Casey, Darren P.;Madery, Brandon D.;Joyner, Michael J.
通讯作者：
Joyner, Michael J.
DOI：
10.1152/ajpheart.2001.281.4.h1734
发表时间：
2001-10-01
影响因子：
4.8
作者：
Lott, MEJ;Hogeman, CS;MacLean, DA
通讯作者：
MacLean, DA