A simple method for individual anaerobic threshold as predictor of max lactate steady state

Background: The individual anaerobic threshold (IAT) is defined (18) as the highest metabolic rate where blood lactate (La) concentrations are maintained at a steady-state during prolonged exercise. Stegmann et al.'s (18) method to detect IAT, using La-performance relationship during incremental graded exercise, is based on the assumption that La is in relatively steady state by the end of each 3-min stage of work rate. However, at the end of a 3-min stage, an La steady state (Lass) is not reached (13). Purpose: The present study was designed to investigate whether the IAT should be determined by attributing La value to the antecedent stage (IAT(a)) or to the same stage of its measurement (IAT(m)), then to verify whether this IAT would be a valid indicator of the max Lass during prolonged exercise. Methods: Forty-one athletes (21 male and 20 female), regularly involved in different physical training, performed three exercise tests on treadmill. The first one was a 5-min stage incremental test to detest the IAT(a) and IAT(m). The other two tests were 30-min prolonged tests at the IAT(a) and IAT(m) workload. Lass were present in IAT(a) intensity (about 4.0 mmol.L-1) both in male and female athletes, whereas at IAT(m) intensity a Lass was not present and a premature break-off occurred in some cases. Discussion: This protocol can be useful for practical use because: 1) the method of choosing the anaerobic threshold is easy to apply; 2) it does not require to reach the maximal effort; and 3) although in some cases the IAT, could probably underestimate the workload of max Lass, the IAT(a) can be regarded as guideline to define the intensity of endurance training.