The effect of preceding anaerobic exercise on aerobic and anaerobic work

The effects of exercise-induced elevation of lactic acid concentration in blood [La_b] up to 12-14 mM on the subsequent aerobic (≤ {Mathematical expression}O₂ max) and anaerobic (supramaximal) performance was investigated in a group of trained non-athletic subjects. For submaximal loads ranging from 0.6 {Mathematical expression}O₂ max to {Mathematical expression}O₂ max the {Mathematical expression}O₂ max/external work load (-W^ext) ratio was unaffected by preceding anaerobic exercise, {Mathematical expression}O₂ max was not significantly different, whereas the maximal performance time of a standard exercise was reduced. The kinetics of the {Mathematical expression}O₂ on- adjustment at the onset of 0.9 {Mathematical expression}O₂ max rectangular loads carried out by the arms and/or by the legs was significantly increased by a preceding supramaximal anaerobic load carried out by the same as well as by the non-exercised limbs. It is concluded that in the presence of high [La_b] (1) the maximal aerobic power {Mathematical expression}O₂ max) is unchanged; (2) the efficiency of aerobic work is unaffected, which implies that during active recovery most La is used as substrate, provided the metabolic level during the latter exceeds 0.6 {Mathematical expression}O₂ max; (3) the endurance for anaerobic as well as for aerobic exercise is reduced; (4) the kinetics of the {Mathematical expression}O₂ adjustment at the onset of submaximal rectangular loads is faster, both in primed and in non-exercised muscles.