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Plasma Acidosis and Peak Power after a Supramaximal Trial in Elite Sprint and Endurance Cyclists: Effect of Bicarbonate.
Mildenhall, Mathew J; Maunder, E D; Plews, Daniel J; Lindinger, Michael I; Cairns, Simeon P.
Afiliação
  • Maunder ED; SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, NEW ZEALAND.
  • Plews DJ; SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, NEW ZEALAND.
  • Lindinger MI; Research and Development, The Nutraceutical Alliance, Burlington, Ontario, CANADA.
  • Cairns SP; SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, NEW ZEALAND.
Med Sci Sports Exerc ; 55(5): 932-944, 2023 05 01.
Article em En | MEDLINE | ID: mdl-36729629
ABSTRACT

PURPOSE:

This study aimed to determine whether (i) a plasma acidosis contributes to a reduction of mechanical performance and (ii) bicarbonate supplementation blunts plasma acidosis and arterial oxygen desaturation to resist fatigue during the end spurt of a supramaximal trial in elite sprint and endurance cyclists.

METHODS:

Elite/world-class cyclists ( n = 6 sprint, n = 6 endurance) completed two randomized, double-blind, crossover trials at 105%V̇O 2peak simulating 3 min of a 4-km individual pursuit, 90 min after ingestion of 0.3 g·kg -1 BM sodium bicarbonate (BIC) or placebo (PLA). Peak power output (PPO), optimal cadence and optimal peak torque, and fatigue were assessed using a 6-s "all-out sprint" before (PPO1) and after (PPO2) each trial. Plasma pH, bicarbonate, lactate - , K + , Na + , Ca 2+ , and arterial hemoglobin saturation (SpO 2 (%)), were measured.

RESULTS:

Sprint cyclists exhibited a higher PPO, optimal pedal torque, and anaerobic power reserve (APR) than endurance cyclists. The trial reduced PPO (PLA) more for sprint (to 47% initial) than endurance cyclists (to 61% initial). Optimal cadence fell from ~151 to 92 rpm and cyclists with higher APR exhibited a reduced optimal peak torque. Plasma pH fell from 7.35 to 7.13 and plasma [lactate - ] increased from 1.2 to 19.6 mM (PLA), yet neither correlated with PPO loss. Sprint cyclists displayed a lesser plasma acidosis but greater fatigue than endurance cyclists. BIC increased plasma [HCO 3- ] (+6.8 mM) and plasma pH after PPO1 (+0.09) and PPO2 (+0.07) yet failed to influence mechanical performance. SpO 2 fell from 99% to 96% but was unrelated to the plasma acidosis and unaltered with BIC.

CONCLUSIONS:

Plasma acidosis was not associated with the decline of PPO in a supramaximal trial with elite cyclists. BIC attenuated acid-base disturbances yet did not improve arterial oxygen desaturation or mechanical performance at the end-spurt stage.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Acidose / Bicarbonatos Tipo de estudo: Clinical_trials Limite: Humans Idioma: En Revista: Med Sci Sports Exerc Ano de publicação: 2023 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Acidose / Bicarbonatos Tipo de estudo: Clinical_trials Limite: Humans Idioma: En Revista: Med Sci Sports Exerc Ano de publicação: 2023 Tipo de documento: Article
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