Osada Takuya, Rådegran Göran
The Copenhagen Muscle Research Centre, University of Copenhagen, and Rigshospitalet, DK-2100 Copenhagen Ø, Denmark.
J Appl Physiol (1985). 2002 Mar;92(3):1325-30. doi: 10.1152/japplphysiol.00848.2001.
Whether limb blood flow is directly regulated to match the work rate, independent of the rate of contraction, remains elusive. This study therefore investigated the relationship between femoral arterial blood flow (FABF; Doppler ultrasound) and "external" (applied load) as well as "total" [external + "internal" (potential and kinetic energy changes of the moving lower leg)] work rate, during steady-state one-legged, dynamic, knee extensor exercise (1L-KEE) in the sitting position at different contraction rates. Ten subjects performed 1L-KEE at 30, 60, and 90 contractions/min (cpm) 1) at constant resistive loads of 0.2 and 0.5 kg inducing incremental external work rates (study I) and 2) at different relative resistive loads inducing constant external work rates of 9 and 18 W (study II). Moreover, 3) six subjects performed 1L-KEE at 60 and 100 cpm at incremental total work rates of 40, 50, 60, and 70 W (study III). In study I, FABF increased (P < 0.001) with increasing contraction frequency and external work rate, for each resistive load. In study II, FABF increased (P < 0.001) with increasing contraction frequency for each constant external work rate. Of major importance in study III, however, was that FABF, although increasing linearly with the total work rate, was not different (P = not significant) between contraction rates, at the total work rates of 40, 50, 60, and 70 W, respectively. Furthermore, FABF correlated linearly and positively with both the external and total work rate for each contraction frequency. In conclusion, the findings support the concept that leg blood flow during 1L-KEE in a normal knee extensor ergometer is matched directly in relation to the total work rate and metabolic activity, irrespective of the contraction frequency. The rate of contraction seems erroneously to influence the results only when it is related to the external work rate without taking into account the internal work component.
肢体血流是否直接受到调节以匹配工作率，而与收缩速率无关，这一点仍不清楚。因此，本研究调查了在不同收缩速率下，坐姿单腿动态伸膝运动（1L-KEE）的稳态过程中，股动脉血流（FABF；多普勒超声）与“外部”（施加负荷）以及“总”[外部+“内部”（小腿运动的势能和动能变化）]工作率之间的关系。10名受试者在30、60和90次收缩/分钟（cpm）的频率下进行1L-KEE：1）在0.2和0.5千克的恒定阻力负荷下，诱导递增的外部工作率（研究I）；2）在不同的相对阻力负荷下，诱导9和18瓦的恒定外部工作率（研究II）。此外，3）6名受试者在60和100 cpm的频率下进行1L-KEE，总工作率递增，分别为40、50、60和70瓦（研究III）。在研究I中，对于每个阻力负荷，FABF随着收缩频率和外部工作率的增加而增加（P < 0.001）。在研究II中，对于每个恒定的外部工作率，FABF随着收缩频率的增加而增加（P < 0.001）。然而，在研究III中至关重要的是，尽管FABF随着总工作率呈线性增加，但在40、50、60和70瓦的总工作率下，收缩速率之间没有差异（P = 不显著）。此外，对于每个收缩频率，FABF与外部和总工作率均呈线性正相关。总之，研究结果支持这样一个概念，即在正常伸膝测力计上进行1L-KEE时，腿部血流与总工作率和代谢活动直接匹配，而与收缩频率无关。仅当收缩速率与外部工作率相关而未考虑内部工作成分时，收缩速率似乎错误地影响了结果。
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