Efeito da suplementação aguda de guaraná (Paullinia Cupana) e de uma dose equivalente de cafeína sobre parâmetros de potência muscular na execução do exercício supino reto

Abstract

Introduction: Guarana (Paullinia Cupana) is a natural substance rich in caffeine and other bioactive components. It is known that its acute ingestion can improve cognitive performance and effort perception parameters, but it is still unclear whether this ingestion can be efficient as an ergogenic substance in the production of muscular power, and whether this possible ergogenic effect is due to its caffeine concentration Objective: The objective of the present research was to compare the effect of acute ingestion of Guaraná (Paullinia Cupana) with an equivalent dose of caffeine on muscle power parameters. Methods: 34 individuals (18 to 35 years old) practicing resistance training were recruited and randomized into three experimental situations: PLACEBO (PLA); 500mg of guarana (GUA-500, containing 130mg of caffeine) and 130mg of caffeine (CAF-130). The individuals underwent a familiarization session with the bench press exercise performed on the Smith machine, in which the individuals' 1RM value and the optimal load for power production were measured. After a minimum interval of 48 hours from the 1RM test and optimal load, the individuals performed, on different days, the three experimental sessions in a randomized order: acute ingestion of caffeine, placebo or Guarana. Each experimental situation had a minimum washout interval of two days. A percentage of optimal load for power production was estimated through a progressive test on the bench press using only the bar, 30%, 40%, 50% and 60% of 1RM in order to identify the best load to perform 3 sets up to 40% of the loss of movement speed, with a 5-minute break between sets. Before performing the physical task, the individuals performed two sets of five repetitions using the load identified as optimal, with a 3-minute break between each set. warm-up series. Participants performed the concentric phase of movement performed at maximum intentional speed, and the eccentric phase lasting 2 seconds, in which the following variables were measured: average power (Watts), peak power (Watts), peak speed (m/s), and average propulsive speed (m/s). Results: Regarding the number of repetitions achieved between the experimental situations, no statistically significant difference was identified between the factors capsule ingested (F(2, 264) = 1.4689, P = 0.2320; partial η² = 0.01); between the three series performed (F(2, 264 = 0.5775, P = 0.5620) and in relation to Capsule: Series (F = 0.2937, P = 0.8819), in relation to Peak Power, the analyzes did not detect any significant effect on the values Capsule (F (2,264) = 0.0908; P = 0.7479), Series (F (2, 264) = 1.5053; P = 0.2238) and for the interactions Capsule: Series (F (4, 264) = 0.7674; P = 0.5453), regarding Average Power, the analysis did not detect significant effects for the Capsule factors (F (2, 264) = 0.028; P = 0.972; partial η² < 0.01), Series (F (2, 264) = 1.187; P = 0.306; partial η² < 0.01), and for the Capsule interaction: series (F (4,264) = 1.266; P = 0.283; partial η² = 0.02), as for Peak Speed, the analysis indicated no effect for the Capsule factor (F (2,263) = 1.162; P = 0.314; partial η² < 0.01), a significant effect for the factor Series (F (2, 263) = 3, 479; P = 0.03; partial η² = 0.03), in the Capsule:series interaction analysis (F (4, 263) = 1, 337; P = 0.256 ; partial η² = 0.02), no significant effect was identified. With regard to Average propulsive speed, no significant differences were identified for the factors Capsule (F (2, 264) = 0.401; P = 0.669; partial η² = 0.01), Series (F (2,264) = 1 , 327; P = 0.266; partial η² < 0.01) and for the Capsule: series interaction (F (4, 264) = 1.199; P = 0.311; partial η² < 0.01). Conclusion: Supplementation with 500mg of Guarana containing 130mg and 130mg of caffeine alone did not trigger any ergogenic effect on muscle power parameters and bench press speed.