SODIUM BICARBONATE SUPPLEMENTATION IMPROVES PERFORMANCE IN ISOMETRIC FATIGUE PROTOCOL

• Main Authors: Cezar Augusto Souza Casarin, Rafael Ambrósio Battazza, Marco Aurélio Lamolha, Marcelo Martins Kalytczak, Fabiano Politti, Alexandre Lopes Evangelista, Andrey Jorge Serra, Roberta Luksevicius Rica, Marcos Rodolfo Ramos Paunksnis, Caue Vazquez La Scala Teixeira, Aylton Figueira Junior, Danilo Sales Bocalini
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Medicina do Esporte
• Series: Revista Brasileira de Medicina do Esporte
• Subjects: Fatiga muscular; Bicarbonato de sodio; Alcalosis; Ejercicio
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-86922019000100040&lng=en&tlng=en

ABSTRACT Introduction: Although sodium bicarbonate (NaHCO3) supplementation has been shown to decrease fatigue and improve high-intensity exercise performance, the effects on maintenance of isometric contractions are not clear. Objective: To investigate the effect of NaHCO3 on the performance of individuals subjected to a fatigue protocol in an isometric exercise on the isokinetic dynamometer. Methods: Participants were 12 men in a randomized, double-blind, crossover, placebo-controlled trial. Sixteen minutes after the intake of 0.3 g/kg of body mass of NaHCO3 or placebo, the participants performed an isometric fatigue protocol of right knee extension exercises during eight minutes at 70% of maximum voluntary isometric contraction. The fatigue indicator was the time point at which torque was reduced to 50% of the initial value. The length of resistance was assessed by maintaining the task over 50% of the initial torque. Lactate/blood pH concentrations and rate of perceived exertion (RPE) and pain (RPP) indexes were analyzed. The RPE of the session was evaluated 30 minutes after the test. Results: Blood pH was higher in pre-protocol and in the fatigue indicator after NaHCO3 intake, as were the blood lactate concentrations in the fatigue indicator and at the end of the protocol (p<0.001). NaHCO3 supplementation increased the time to fatigue and lessened the rate of decline of isometric peak torque at the end of the protocol (p<0.001). RPE and RPP were smaller at the end of the protocol in the NaHCO3 condition, and the RPE of the session was diminished (p<0.001). Conclusion: NaHCO3 supplementation enhances steady isometric contraction performance and reduces the internal load. Level of Evidence II; Diagnostic studies - Investigation of an examination for diagnosis.