Time To Exhaustion At The Onset Of Blood Lactate Accumulation In Runners With Different Athletic Ability

Revista Brasileira de Medicina do Esporte

The following lines show the abstract of the article called “Time To Exhaustion At The Onset Of Blood Lactate Accumulation In Runners With Different Athletic Ability”, which was written in English by Jordan Santos-Concejero, Cristina Granados, Jon Irazusta, Iraia Bidaurrazaga-Letona, Jon Zabala-Lili and Susana Gil, and published in Revista Brasileira de Medicina do Esporte – Vol. 19, No 4 – Jul/Aug, 2013

Objective: To characterize the physiological responses of runners of different athletic ability at the velocity at onset of blood lactate (VOBLA) 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 VOBLA (Test 1), and then another one at the corresponding VOBLA 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 (TET2). The individual lactate threshold velocity (VLT) and lactate concentration ([La-1]LT) were calculated according to the D-max method.

Results: VOBLA and VLT were higher in well-trained runners (P<0.001). [La-1]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 VOBLA than at VLT (P<0.001). Well-trained runners ran a shorter TET2 than the trained runners (P<0.05). Moreover, well-trained runners presented a higher respiratory rate at 50, 80 and 90% of TET2 and VO2 at 20-100% of TET2 (P<0.05). TET2 was inversely correlated (P<0.01) with VOBLA and positively with personal best 10-km performance (P<0.01). VOBLA was positively correlated with the %VO2max 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: VOBLA may not be accurate for programming running training sessions or for performing an evaluation of aerobic capacity.

 

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