Shoemaker J K, Phillips S M, Green H J, Hughson R L
Department of Kinesiology, University of Waterloo, Ont., Canada.
Cardiovasc Res. 1996 Feb;31(2):278-86.
The hypothesis that the adaptation to endurance exercise training included a faster increase in blood flow at the onset of exercise was tested in 12 healthy young men who endurance-trained (ET) 2 h/day, for 10 days at 65% VO2 peak on a cycle ergometer, and in 11 non-training control (C) subjects.
Blood flow was estimated from changes in femoral artery mean blood velocity (MBV) by pulsed Doppler. Beat-by-beat changes in cardiac output (CO) and mean arterial pressure (MAP) were obtained by impedance cardiography and a Finapres finger cuff, respectively. MBV, MAP and CO were measured at rest and during 5 min of dynamic knee extension exercise. Both legs worked alternately with 2 s raising and lowering a weight (15% maximal voluntary contraction) followed by 2 s rest while the other leg raised and lowered the weight.
In the ET group the time to 63% (T63%) of the approximately exponential increase in MBV following 10 days of training (8.6 +/- 1.2 s, mean +/- s.e.) was significantly faster than the Day 0 response (14.2 +/- 2.1 s, P < 0.05). The T63% of femoral artery vascular conductance (VCfa) was also faster following 10 days of ET (9.4 +/- 0.9 s) versus Day 0 (16.0 +/- 2.5 s) (0.05). There was no change in the T63% of both MBV and VCfa for the C group. The kinetics of CO were not significantly affected by ET, but the amplitude of CO in the adaptive phase, and at steady state, were significantly greater (P < 0.05) at Day 10 compared to Day 0 for the ET group with no change in the C group.
These data supported the hypothesis that endurance training resulted in faster adaptation of blood flow to exercising muscle, and further showed that this response occurred early in the training program.
在12名健康年轻男性中测试了如下假设，即耐力运动训练的适应性包括运动开始时血流增加更快。这些男性在自行车测力计上以65%的最大摄氧量进行每天2小时、为期10天的耐力训练（ET组），并与11名非训练对照（C组）受试者进行比较。
通过脉冲多普勒根据股动脉平均血流速度（MBV）的变化估算血流。分别通过阻抗心动图和Finapres指套袖带获得心输出量（CO）和平均动脉压（MAP）的逐搏变化。在静息状态和动态伸膝运动5分钟期间测量MBV、MAP和CO。双腿交替工作，每2秒举起和放下一个重物（最大自主收缩的15%），然后休息2秒，同时另一条腿举起和放下重物。
在ET组中，训练10天后MBV近似指数增加至63%（T63%）的时间（8.6±1.2秒，平均值±标准误）显著快于第0天的反应（14.2±2.1秒，P<0.05）。ET训练10天后股动脉血管传导率（VCfa）的T63%（9.4±0.9秒）也快于第0天（16.0±2.5秒）（P<0.05）。C组的MBV和VCfa的T63%没有变化。ET对CO的动力学没有显著影响，但ET组在第10天适应性阶段和稳定状态下CO的幅度与第0天相比显著更大（P<0.05），C组没有变化。
这些数据支持了耐力训练导致血流更快适应运动肌肉的假设，并进一步表明这种反应在训练计划早期就出现了。
