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 $\dot{V}$O_2max at MLSS (%$\dot{V}$O_{2_MLSS}) are decisive for endurance performance. We tested the hypotheses that (1) %$\dot{V}$O_{2_MLSS} is positively correlated with the ability to sustain a high fraction of $\dot{V}$O_2max for a given competition duration (%$\dot{V}$O_{2_TT}); (2) %$\dot{V}$O_{2_MLSS} improves the prediction of the average power output of a time trial (PO_{_TT}) in addition to $\dot{V}$O_2max and gross efficiency (GE); (3) PO_{_MLSS} improves the prediction of PO_{_TT} in addition to $\dot{V}$O_2max 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 $\dot{V}$O_2max, and 20-min time trials for %$\dot{V}$O_{2_TT} and PO_{_TT}. Hypothesis 1 was tested via bivariate and partial correlations between %$\dot{V}$O_{2_MLSS} and %$\dot{V}$O_{2_TT}. Multiple regression models with $\dot{V}$O_2max, GE, ∆PO_LEmin, and %$\dot{V}$O_{2_MLSS} (Hypothesis 2) or PO_{_MLSS} instead of %$\dot{V}$O_{2_MLSS} (Hypothesis 3), respectively, as predictors, and PO_{_TT} as the dependent variable were used to test the hypotheses.

Results

%$\dot{V}$O_{2_MLSS} was not correlated with %$\dot{V}$O_{2_TT} (r = 0.17, p = 0.583). Neither %$\dot{V}$O_{2_MLSS} (p = 0.424) nor PO_{_MLSS} (p = 0.208) did improve the prediction of PO_{_TT} in addition to $\dot{V}$O_2max and GE.

Conclusion

These results challenge the assumption that PO_{_MLSS} or %$\dot{V}$O_{2_MLSS} are independent predictors of supra-MLSS PO_{_TT} and %$\dot{\text{V}}$O_{2_TT}.