Hoelting B D, Scheuermann B W, Barstow T J
Department of Kinesiology, Kansas State University, Manhattan, Kansas 66506-0302, USA.
J Appl Physiol (1985). 2001 Aug;91(2):671-9. doi: 10.1152/jappl.2001.91.2.671.
Previous studies in isolated muscle preparations have shown that muscle blood flow becomes compromised at higher contraction frequencies. The purpose of this study was to examine the effect of increases in contraction frequency and muscle tension on mean blood flow (MBF) during voluntary exercise in humans. Nine male subjects [23.6 +/- 3.7 (SD) yr] performed incremental knee extension exercise to exhaustion in the supine position at three contraction frequencies [40, 60, and 80 contractions/min (cpm)]. Mean blood velocity of the femoral artery was determined beat by beat using Doppler ultrasound. MBF was calculated by using the diameter of the femoral artery determined at rest using echo Doppler ultrasound. The work rate (WR) achieved at exhaustion was decreased (P < 0.05) as contraction frequency increased (40 cpm, 16.2 +/- 1.4 W; 60 cpm, 14.8 +/- 1.4 W; 80 cpm, 13.2 +/- 1.3 W). MBF was similar across the contraction frequencies at rest and during the first WR stage but was higher (P < 0.05) at 40 than 80 cpm at exercise intensities >5 W. MBF was similar among contraction frequencies at exhaustion. In humans performing knee extension exercise in the supine position, muscle contraction frequency and/or muscle tension development may appreciably affect both the MBF and the amplitude of the contraction-to-contraction oscillations in muscle blood flow.
以往对离体肌肉标本的研究表明，在较高的收缩频率下肌肉血流会受到影响。本研究的目的是探讨在人体自愿运动过程中，收缩频率和肌肉张力增加对平均血流（MBF）的影响。9名男性受试者[23.6±3.7（标准差）岁]在仰卧位以三种收缩频率[40、60和80次/分钟（cpm）]进行递增式膝关节伸展运动直至力竭。使用多普勒超声逐搏测定股动脉的平均血流速度。MBF通过使用静息时用回声多普勒超声测定的股动脉直径来计算。随着收缩频率增加（40 cpm，16.2±1.4 W；60 cpm，14.8±1.4 W；80 cpm，13.2±1.3 W），力竭时达到的工作率（WR）降低（P<0.05）。在静息时和第一个WR阶段，各收缩频率下的MBF相似，但在运动强度>5 W时，40 cpm时的MBF高于80 cpm（P<0.05）。力竭时各收缩频率下的MBF相似。在仰卧位进行膝关节伸展运动的人体中，肌肉收缩频率和/或肌肉张力的发展可能会显著影响MBF以及肌肉血流中收缩间振荡的幅度。
