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

Area of Science:

• Exercise Physiology
• Sports Science
• Endurance Performance

Background:

• Maximal lactate steady state (MLSS) is often considered a crucial determinant of endurance performance.
• High power output at MLSS (PO_MLSS) and high fraction of VO2max at MLSS (%VO2_MLSS) are hypothesized to be decisive for performance.
• This study investigates the predictive value of these MLSS-related metrics for endurance capacity.

Purpose of the Study:

• To test if %VO2_MLSS correlates with the ability to sustain a high VO2max fraction during a time trial (%VO2_TT).
• To determine if %VO2_MLSS improves the prediction of time trial power output (PO_TT) beyond VO2max and gross efficiency (GE).
• To assess if PO_MLSS enhances PO_TT prediction when VO2max and GE are already considered.

Main Methods:

• Twenty-one participants underwent incremental tests, 30-min constant load tests for MLSS, ramp tests for VO2max, and 20-min time trials.
• Correlations were used to assess the relationship between %VO2_MLSS and %VO2_TT.
• Multiple regression models predicted PO_TT using VO2max, GE, and either %VO2_MLSS or PO_MLSS.

Main Results:

• %VO2_MLSS was not significantly correlated with %VO2_TT (r=0.17, p=0.583).
• Neither %VO2_MLSS (p=0.424) nor PO_MLSS (p=0.208) significantly improved the prediction of PO_TT when VO2max and GE were included in the model.

Conclusions:

• The findings challenge the notion that PO_MLSS and %VO2_MLSS are independent predictors of time trial performance.
• These metrics do not appear to be critical for predicting performance in supra-MLSS events.
• Endurance performance prediction may rely more on VO2max and gross efficiency than MLSS-derived parameters.