Caffeine Ingestion Increases Estimated Glycolytic Metabolism during Taekwondo Combat Simulation but Does Not Improve Performance or Parasympathetic Reactivation

Autor(es)

Paulo Lopes-Silva, Joao ^[1] ; da Silva Santos, Jonatas Ferreira ^[1] ; Magnani Branco, Braulio Henrique ^[1] ; Cal Abad, Cesar Cavinato ^[2] ; de Oliveira, Luana Farias ^[3] ; Loturco, Irineu ^{[1, 2]} ; Franchini, Emerson ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Phys Educ & Sport, Martial Arts & Combat Sports Res Grp, Sao Paulo - Brazil

^[2] NAR Nucleus High Performance Sport, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Sch Phys Educ & Sport, Lab Appl Nutr & Metab, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 10, n. 11 NOV 5 2015.
• Citações Web of Science: 15

Resumo

Objectives The aim of this study was to evaluate the effect of caffeine ingestion on performance and estimated energy system contribution during simulated taekwondo combat and on post-exercise parasympathetic reactivation. Methods Ten taekwondo athletes completed two experimental sessions separated by at least 48 hours. Athletes consumed a capsule containing either caffeine (5 mg.kg(-1)) or placebo (cellulose) one hour before the combat simulation (3 rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration and rating of perceived exertion were measured before and after each round, while heart rate (HR) and the estimated contribution of the oxidative (W-AER), ATP-PCr (W-PCR), and glycolytic (W{[}La-]) systems were calculated during the combat simulation. Furthermore, parasympathetic reactivation after the combat simulation was evaluated through 1) taking absolute difference between the final HR observed at the end of third round and the HR recorded 60-s after (HRR60s), 2) taking the time constant of HR decay obtained by fitting the 6-min post-exercise HRR into a first-order exponential decay curve (HRR tau), or by 3) analyzing the first 30-s via logarithmic regression analysis (T30). Results Caffeine ingestion increased estimated glycolytic energy contribution in relation to placebo (12.5 +/- 1.7 kJ and 8.9 +/- 1.2 kJ, P = 0.04). However, caffeine did not improve performance as measured by attack number (CAF: 26. 7 +/- 1.9; PLA: 27.3 +/- 2.1, P = 0.48) or attack time (CAF: 33.8 +/- 1.9 s; PLA: 36.6 +/- 4.5 s, P = 0.58). Similarly, RPE (CAF: 11.7 +/- 0.4 a.u.; PLA: 11.5 +/- 0.3 a.u., P = 0.62), HR (CAF: 170 +/- 3.5 bpm; PLA: 174.2 bpm, P = 0.12), oxidative (CAF: 109.3 +/- 4.5 kJ; PLA: 107.9 kJ, P = 0.61) and ATP-PCr energy contributions (CAF: 45.3 +/- 3.4 kJ; PLA: 46.8 +/- 3.6 kJ, P = 0.72) during the combat simulation were unaffected. Furthermore, T30 (CAF: 869.1 +/- 323.2 s; PLA: 735.5 +/- 232.2 s, P = 0.58), HRR60s (CAF: 34 +/- 8 bpm; PLA: 38 +/- 9 bpm, P = 0.44), HRRt (CAF: 182.9 +/- 40.5 s, PLA: 160.3 +/- 62.2 s, P = 0.23) and HRRamp (CAF: 70.2 +/- 17.4 bpm; PLA: 79.2 +/- 17.4 bpm, P = 0.16) were not affected by caffeine ingestion. Conclusions Caffeine ingestion increased the estimated glycolytic contribution during taekwondo combat simulation, but this did not result in any changes in performance, perceived exertion or parasympathetic reactivation. (AU)

• Processo FAPESP: 11/19513-2 - Efeitos da Suplementação Crônica de Beta-Alanina Combinada ou não à Ingestão Aguda de Bicarbonato de Sódio sobre a Concentração Pico de Carnosina, o "Washout" de Carnosina e o Desempenho em Exercício Intenso.
• Beneficiário: Bryan Saunders
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado