Is the Functional Threshold Power a Valid Metric to Estimate the Maximal Lactate Steady State in Cyclists?

• Autores: José Ramón Lillo Beviá, Javier Courel Ibáñez, Victor Cerezuela Espejo, Ricardo José Morán Navarro, Alejandro Martínez Cava, Jesús García Pallarés
• Localización: Journal of strength and conditioning research: the research journal of the NSCA, ISSN 1064-8011, Vol. 36, Nº. 1, 2022, págs. 167-173
• Idioma: inglés
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• Resumen

  • The aims of this study were to determine (a) the repeatability of a 20-minute time-trial (TT20), (b) the location of the TT20 in relation to the main physiological events of the aerobic-anaerobic transition, and (c) the predictive power of a list of correction factors and linear/multiple regression analysis applied to the TT20 result to estimate the individual maximal lactate steady state (MLSS). Under laboratory conditions, 11 trained male cyclists and triathletes (V[Combining Dot Above]O2max 59.7 +/- 3.0 ml[middle dot]kg-1[middle dot]min-1) completed a maximal graded exercise test to record the power output associated with the first and second ventilatory thresholds and V[Combining Dot Above]O2max measured by indirect calorimetry, several 30 minutes constant tests to determine the MLSS, and 2 TT20 tests with a short warm-up. Very high repeatability of TT20 tests was confirmed (standard error of measurement of +/-3 W and smallest detectable change of +/-9 W). Validity results revealed that MLSS differed substantially from TT20 (bias = 26 +/- 7 W). The maximal lactate steady state was then estimated from the traditional 95% factor (bias = 12 +/- 7 W) and a novel individual correction factor (ICF% = MLSS/TT20), resulting in 91% (bias = 1 +/- 6 W). Complementary linear (MLSS = 0.7488 x TT20 + 43.24; bias = 0 +/- 5 W) and multiple regression analysis (bias = 0 +/- 4 W) substantially improved the individual MLSS workload estimation. These findings suggest reconsidering the TT20 procedures and calculations to increase the effectiveness of the MLSS prediction.