The fatigue threshold (rheta_F) in humans : Its physiological bases and applications

已经多次证明，人类对高强度运动的耐受时间(T)是功率(P)的双曲线函数，其渐近线被称为“疲劳阈值”(Rheta_F)，即(P-Rheta_F)*t=W‘，其中W’是曲率常数，代表在Rheta_F之上可以进行的恒定量的功。首先，我们研究了两个参数的生理决定因素(S)：Rheta_F和W‘决定P-t双曲线。Rheta_F代表可以维持“准”稳定状态的最高可达到的工作速率，即VO2和血乳酸不会像所有超Rheta_F工作速率那样持续不可阻挡地增加。曲率常数W‘具有功单位，即功率和时间的乘积，因此，它等同于Rheta_F以上的恒定量的能量。W’可以被认为反映了有限的能量存储，例如与厌氧糖酵解相关的磷酸原池和糖原含量，因为W‘与先前建立的无氧能力的指标：最大氧缺乏量有关，并且在我们的实验中，在糖原耗竭的条件下，W’显著减少，而对于W‘作为无氧工作能力的有效性，现在就得出准确的结论还为时过早。其次，以速度(V)作为P的模拟量，对400m田径跑V-t双曲线上的两个参数：V_F和D‘(而不是W’)进行了测量，并对亚优秀运动员在800、1500、5000m跑中的实际速度表现进行了测试。结果表明，各参赛者的V_F-t双曲线：V_F和D‘的确定为赛跑速度的战略性分配提供了有价值的信息。

It has been repeatedly demonstrated that the tolerable duration (t) of high intensity exercise in humans decreases hyperbolically as a function of power (P) with an asymptote that has been termed the "fatigue threshold" (rheta_F), that is, (P-rheta_F)*t=W', where W' is a curvature constant and represents a constant amount of work which can be performed above rheta_F. Firstly, we investigated to clarify the physiological determinant (s) of two parameters : rheta_F and W'determining the P-t hyperbolic curve. rheta_F represented the highest attainable work rate for which a "quasi" steady state can be sustained, i.e., VO_2 and blood lactate do not continue to inctinue inexorably as they do for all supra-rheta_F work rates. The curvature constant W' has the units of work, i.e., the product of power and time, consequently, it is equivalent to a constant amount of energy above rheta_F. The W' could be considered to reflect a finite energy store such as a phosphagen pool and a glycogen content related to anaerobic glycolysis, because W' was associated with previously established indicator of anaerobic capacity : maximal O_2-deficit, and further W' was significantly reduced under glycogen depleted conditions in our experiments, while it would be premature to draw precise conclusions concerning the validity of W' as an anaerobic working capacity. Secondly, we confirmed that the P-hyperbolic relationship was also consisted in running where speed (V) is used as an analog of P.We measured two parameters : V_F and D' (instead of W') in V-t hyperbolic curve in 400m track running and the race pace performance during actual 800,1500, or 5000m distance run in sub-elite athletes. As a result, the determinates of V_F-t hyperbolic curve : V_F and D' in each runner give valuable information for a strategic race pace allocation.