Evaluating a test protocol for predicting maximum lactate steady state

BACKGROUND: Maximum lactate steady state (MLSS) is defined as the highest steady state exercise level one can maintain while also maintaining an equilibrium between the elimination of blood lactate and the diffusion of lactate into the blood. MLSS is an excellent tool for assessing fitness level, predicting endurance performance, and designing training programs. METHODS: This investigation assesses the validity of the Lactate Minimum Test (LMT), which consists of inducing lactic acidosis through a VO2peak test, followed by an eight-minute walking recovery and an incremental exercise test, to determine if the running velocity associated with the minimum lactate value predicts the MLSS velocity. Following this LMT, two constant velocity 28-minute runs were performed, one at the predicted MLSS velocity (trial 1) and the other 0.13 m sec-1 (4-8%) above the predicted MLSS velocity (trial 2). Ten active female subjects participated (32 +/- 7 yrs (mean +/- SD); 65.7 +/- 16.4 kg; VO2peak 40.0 +/- 7.5 ml.kg-1.min-1). RESULTS: During trial 1, there was a -0.6 +/- 0.3 mmol l-1 (mean +/- SE) change in lactate. Based on a definition of lactate steady state (LSS) as less than a 0.5 mmol.l-1 increase, this value signified LSS. A similar comparison during trial 2 revealed a 1.8 +/- 0.3 mmol.l-1 increase in lactate, signifying a workload above LSS and therefore confirming trial 1 as the maximum LSS (MLSS). CONCLUSIONS: These results suggest that the test protocol accurately predicted the MLSS velocity.