Suplementação de cafeína, fadiga mental e desempenho físico em prova de corrida em indivíduos ativos e testes de aptidão física em jogadores de futebol profissional e de base

Abstract

This thesis is composed of an article collection, in which the first original article aimed to evaluate the effect of caffeine intake associated with mental fatigue on physical performance in a 3200 m race. It was a randomized, cross-over study in which 10 physically active male subjects participated, with a mean age of 27.7 ± 8.9 years. They received 6 mg/kg of caffeine or 6 mg/kg of cellulose, after supplementation, they were induced to mental fatigue through a protocol composed of medium and high complexity activities, respectively: cognitive game on the smartphone (30 min) and the modified Stroop test (30 min). Afterward, the individuals performed 8 laps of 400 m of time trial running. A two-way ANOVA was used to compare physical performance, mood state, and other physiological variables between the caffeine and placebo groups. A learning effect on modified Stroop test performance was observed when comparing the first visit with the second, regardless of the supplementations used. However, caffeine supplementation did not improve physical performance during a 3200 m race in physically active individuals with mental fatigue induced. The second original article aimed to investigate the effects of acute caffeine supplementation on physical performance among professional and under-football players. Eighty-one soccer players participated in this study, they were divided into 4 groups according to the type of supplementation and category: caffeine-professional (Caf-P) (n=17), placebo-professional (Pla-P) (n=12), caffeine-under (Caf-U) (n=26) and placebo-under (Pla-U) (n=26). In a randomized, double-blind design, athletes received 6 mg/kg of caffeine or 6 mg/kg of cellulose. After 60 minutes, the players performed a battery of tests to assess flexibility, strength, speed, power, and cardiorespiratory capacity. Caffeine improved performance on strength and speed variables when compared to placebo in both groups. On the other hand, professional athletes presented better physical performance in relation to athletes from basic categories.