Tempo para exaustão no acúmulo de lactato sanguíneo em corredores com diferentes habilidades atléticas

Abstract

Objective: To characterize the physiological responses of runners of different athletic ability at the velocity at onset of blood lactate (V OBLA ) and to determine if 4 mmol·L -1 represents the same relative exercise intensity for every runner. Methods: Eleven trained and twelve well-trained runners completed two running tests on a treadmill: first, a maximal incremental lactate test to calculate the V OBLA (Test 1), and then another one at the corresponding V OBLA until exhaustion (Test 2). Gas exchange and heart rate (HR) were continuously measured and plotted as a percentage of time to exhaustion in Test 2 (TE T2 ). The individual lactate threshold velocity (V LT ) and lactate concentration ([La ] LT was <4 mmol·L -1 in the well-trained runners (P<0.001), but not in trained runners. Well-trained runners were faster at V OBLA than at V LT (P<0.001). Well-trained runners ran a shorter TE T2 than the trained runners (P<0.05). Moreover, well-trained runners presented a higher respiratory rate at 50, 80 and 90% of TE T2 and VO 2 at 20-100% of TE T2 (P<0.05). TE T2 was inversely correlated (P<0.01) with V OBLA and positively with personal best 10-km performance (P<0.01). V OBLA was positively correlated with the %VO 2max in Test 2 (P<0.01). The standard value (4 mmol·L -1 ) for the concentration of blood lactate appears to represent a different exercise intensity for runners of different athletic ability. Conclusion: V OBLA may not be accurated for programming running training sessions or for performing an evaluation of aerobic capacity.