Is the maximal lactate steady state concept really relevant to predict endurance performance?

ABSTRACT

PURPOSE: There is no convincing evidence for the idea that a high power output at the maximal lactate steady state (PO_MLSS) and a high fraction of [Formula see text]O2max at MLSS (%[Formula see text]O2_MLSS) are decisive for endurance performance. We tested the hypotheses that (1) %[Formula see text]O2_MLSS is positively correlated with the ability to sustain a high fraction of [Formula see text]O2max for a given competition duration (%[Formula see text]O2_TT); (2) %[Formula see text]O2_MLSS improves the prediction of the average power output of a time trial (PO_TT) in addition to [Formula see text]O2max and gross efficiency (GE); (3) PO_MLSS improves the prediction of PO_TT in addition to [Formula see text]O2max and GE. METHODS: Twenty-one recreationally active participants performed stepwise incremental tests on the first and final testing day to measure GE and check for potential test-related training effects in terms of changes in the minimal lactate equivalent power output (∆PO_LEmin), 30-min constant load tests to determine MLSS, a ramp test and verification bout for [Formula see text]O2max, and 20-min time trials for %[Formula see text]O2_TT and PO_TT. Hypothesis 1 was tested via bivariate and partial correlations between %[Formula see text]O2_MLSS and %[Formula see text]O2_TT. Multiple regression models with [Formula see text]O2max, GE, ∆PO_LEmin, and %[Formula see text]O2_MLSS (Hypothesis 2) or PO_MLSS instead of %[Formula see text]O2_MLSS (Hypothesis 3), respectively, as predictors, and PO_TT as the dependent variable were used to test the hypotheses. RESULTS: %[Formula see text]O2_MLSS was not correlated with %[Formula see text]O2_TT (r = 0.17, p = 0.583). Neither %[Formula see text]O2_MLSS (p = 0.424) nor PO_MLSS (p = 0.208) did improve the prediction of PO_TT in addition to [Formula see text]O2max and GE. CONCLUSION: These results challenge the assumption that PO_MLSS or %[Formula see text]O2_MLSS are independent predictors of supra-MLSS PO_TT and %[Formula see text]O2_TT.