Binzoni T, Hiltbrand E, Yano T, Cerretelli P
Department of Physiology, University of Geneva, Switzerland.
Acta Physiol Scand. 1997 Mar;159(3):209-15. doi: 10.1046/j.1365-201X.1997.577354000.x.
It is well known that the VO2 readjustment rate of the whole body is faster when carrying out a given constant work load starting from a baseline of moderate exercise than from rest. However, it has not been established whether the above change is the result of faster kinetics of the oxidative machinery or, alternatively, the consequence of a reduced involvement of confounding factors such as anaerobic glycolysis or tissue O2 stores. The problem, earlier approached by chemical methods, was studied in man by 31P-NMRS assessment of the kinetics of phosphocreatine (PC) hydrolysis at the muscle level which is known to reflect the readjustment rate of the oxidative reactions. Twelve normal subjects carried out in a 90 cm bore modified Picker (1.5 T) magnet, a series of contractions by the plantar flexors reaching pre-set submaximal loads either in single steps (constant load, CL) or progressively (incremental exercise. I). If preceding exercise (I), compared to rest, influenced the rate of oxidations, the PC concentration at the target loads would be different for the two exercise modes, reflecting different energy deficits. This was not the case. Thus the present results show that the rate of readjustment of oxidations at the muscle level is not affected by priming exercise confirming previous findings and showing that theoretical models of VO2 control are experimentally applicable to man.
众所周知，从适度运动基线开始执行给定的恒定工作负荷时，全身的VO2重新调整速率比从休息状态开始时更快。然而，上述变化是氧化机制动力学更快的结果，还是诸如无氧糖酵解或组织氧储备等混杂因素参与减少的结果，目前尚未确定。这个问题早期通过化学方法进行研究，现在在人体中通过31P-NMRS评估肌肉水平磷酸肌酸（PC）水解的动力学来进行研究，已知该动力学反映氧化反应的重新调整速率。12名正常受试者在90厘米孔径的改良Picker（1.5T）磁体中，通过足底屈肌进行一系列收缩，以单步（恒定负荷，CL）或逐步（递增运动，I）达到预设的次最大负荷。如果与休息相比，先前的运动（I）影响氧化速率，那么两种运动模式在目标负荷下的PC浓度将有所不同，这反映了不同的能量亏空。但实际并非如此。因此，目前的结果表明，肌肉水平氧化反应的重新调整速率不受预运动的影响，这证实了先前的研究结果，并表明VO2控制的理论模型在实验上适用于人体。
