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Published on: May 18, 2018
A comparison of lactate indices during ramp exercise using modelling techniques and conventional methods
Vincent Thomas1, Frédéric Costes, Michel Chatagnon
1Laboratoire de Physiologie de l'Exercise, Université Jean Monnet de Saint-Etienne, Saint-Etienne, France.
Journal of Sports Sciences
|October 17, 2008
Summary
This study found that breakpoint models for lactate thresholds showed poor agreement with conventional methods. Simpler indices like LT(4), LSI, and Dmax are more reliable for determining exercise intensity.
Area of Science:
- Exercise Physiology
- Sports Science
- Biochemistry
Background:
- Lactate thresholds are crucial for determining exercise intensity.
- Conventional methods and breakpoint models are used to identify these thresholds.
- Comparing the accuracy of different lactate threshold determination methods is essential for performance optimization.
Purpose of the Study:
- To compare lactate indices from single- and double-breakpoint models with conventional lactate threshold methods.
- To evaluate the agreement between various lactate modeling techniques and established protocols.
- To determine the reliability of different lactate threshold detection methods in exercise testing.
Main Methods:
- Eight participants underwent a ramp exercise test on a cycle ergometer.
- Arterial blood samples were collected to measure lactate concentrations.
- Lactate thresholds were determined using LT(4), Delta1 mM, ventilatory parameters, and various modeling techniques (LSI, Dmax, SLog, Mod P, Mod M).
Main Results:
- Single- and double-breakpoint models (Mod P, Mod M) demonstrated poor agreement with other methods.
- LT(4), Dmax, LSI, and respiratory exchange ratio (RER) equal to 1 showed strong correlations (R = 0.81–0.92).
- The mean differences between LT(4), Dmax, LSI, and RER=1 were small, with acceptable limits of agreement.
Conclusions:
- Breakpoint models are questionable for detecting lactate thresholds.
- LT(4), LSI, Dmax, and RER=1 provide reliable and comparable indices of lactate thresholds.
- These findings suggest simpler methods are sufficient for identifying critical exercise intensities.
