Modeling Intermittent Cycling Performance in Hypoxia Using the Critical Power Concept.

• Autores: Samantha Shearman, Dan B. Dwyer, Philip F. Skiba, Nathan Townsend
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 48, Nº. 3, 2016, págs. 527-535
• Idioma: inglés
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• Resumen

  • AB Purpose: This study investigated the efficacy of an intermittent critical power (CP) model, termed the "work-balance" (W'BAL) model, during high-intensity exercise in hypoxia (HYPO). Methods: Eleven trained male cyclists (mean +/- SD age, 27 +/- 6.6 yr; V[spacing dot above]O2peak, 4.79 +/- 0.56 L[middle dot]min-1) completed a maximal ramp test and a 3-min "all-out" test to determine CP and work performed above CP (W'). On another day, an intermittent exercise test to task failure was performed. All procedures were performed in normoxia (NORM) and HYPO (FiO2 [almost equal to] 0.155) in a single-blind, randomized, and counter-balanced experimental design. The W'BAL model was used to calculate the minimum W' (W'BALmin) achieved during the intermittent test. The W'BALmin in HYPO was also calculated using CP + W' derived in NORM (N + H). Results: In HYPO, there was an 18% decrease in V[spacing dot above]O2peak (4.79 +/- 0.56 vs 3.93 +/- 0.47 L[middle dot]min-1; P < 0.001) and a 9% decrease in CP (347 +/- 45 vs 316 +/- 46 W; P < 0.001). No significant change for W' occurred (13.4 +/- 3.9 vs 13.7 +/- 4.9 kJ; P = 0.69; NORM vs HYPO). The change in V[spacing dot above]O2peak was significantly correlated with the change in CP (r = 0.72; P = 0.01). There was no difference between NORM and HYPO for W'BALmin (1.1 +/- 0.9 kJ vs 1.2 +/- 0.6 kJ). The N + H analysis grossly overestimated W'BALmin (7.8 +/- 3.4 kJ) compared with HYPO (P < 0.001). Conclusion: The W'BAL model produced similar results in HYPO and NORM, but only when model parameters were determined under the same environmental conditions as the performance task. Application of the W'BAL model at altitude requires a modification of the model or that CP and W' are measured at altitude