An evaluation of the maximal anaerobic capacity in man

Maximal anaerobic capacity, i.e., the maximal amount of energy released by anaerobic processes (Ean max, J.kg-1), has been evaluated from maximal increase of plasma lactate concentration (Lâp) in eight male subjects of different physical fitness submitted to supramaximal runs of various intensity performed until volitional exhaustion (temps-limite, tlim). As previously found (2), the interindividual differences of tlim were reduced when exercise intensity was expressed by the anaerobic component of exercise defined as the difference between the overall energy requirement (E, W.kg-1) and maximal aerobic power Eox max, W.kg-1). Within the range of intensity studied, Lâp did not vary significantly as a function of E-Eox max. However, the performances achieved by the less fit subjects (group 1) remained lower than those achieved by the more athletic subjects (group 2). Mean Lâp were significantly higher in group 2 (17.2 mmol.l-1 than in group 1 (13.7 mmol.l-1. The rate of increase of Lâp, defined by the ratio Lâp/tlim, was a linear function of E-Eox max. The energy equivalent of plasma lactate accumulation (beta), given by the reciprocal of the slope of the equation describing the relationship Lâp/tlim = f(E-Eox max), amounts 56.8 J.kg-1 when Lâp is increased by 1 mmol.l-1. The energy released by anaerobic glycolysis was calculated by multiplying beta by mean Lâp measured in the two groups of subjects. Assuming that the energy yielded by the anaerobic alactic processes amounts 260 J.kg-1(1), mean Ean max values in group 1 and 2 were found to be equal to 1040 (range:910-1110) and 1240 J.kg-1 (range: 1100-1330), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)