Efeitos psicobiólogicos da suplementação de creatina

Abstract

The belief that some nutritional aid can supposedly improve physical performance is prevalent in sports. Many athletes believe in and emphasize the use of dietary supplements. Creatine is the most studied supplement in the scientific literature and consumed by athletes and practitioners of physical exercise. Users expect to obtain morphophysiological adaptations and thus have a positive influence on performance and body composition. The aim of this study was to evaluate the psychobiological effects of oral creatine supplementation on neuromuscular performance. For this purpose, 12 trained men (25.2 ± 3.4 years; 179.5 ± 4.6 cm; 84.9 ± 8.7 kg) were selected for convenience. All assessments of body composition and neuromuscular performance were performed before and after treatments. Body composition was performed using octapolar bioimpedance. Maximum strength (1RM) and strength endurance (4 sets with maximum repetitions at 70% 1RM) were determined in the bench press exercise. Each subject went through all treatment steps in a crossed and counterbalanced system. The participants received for daily consumption 20 grams of creatine or corn starch added to 10 grams of maltodextrin during 5 days. To investigate the differences between the physiological and psychological effects (placebo) of supplementation, participants were informed during the course of the research that they would receive two types of creatine in order to compare the effects of both to find out if one was superior to the other. Both supplements (creatine or placebo) were placed in pots of the same appearance containing the daily dose. The times of consumption and the amount of water for each dose was standardized throughout the study. During creatine consumption, no significant changes were observed in body weight, fat-free mass, muscle mass and total body water (p > 0.05). With regard to changes in strength manifestations, there were no significant increases in maximum strength (1RM) in both treatments. However, in strength resistance, individuals supplemented with creatine performed more repetitions (CREA: Pre = 23.8 ± 7.9 reps; Pos = 27.3 ± 5.4 reps; ∆ = +14.7%, p = 0.036, g = 0.53 vs PLA: Pre = 25.1 ± 6.9 reps; Pos = 25.4 ± 7.1 reps; ∆ = +1.2%, p = 0.414, g = 0.06), and managed to have a larger total volume (CREA: Pre = 1791 ± 592.4; Pos = 1991 ± 395.4; ∆ = +11.1%, p = 0.038, g = 0.52 vs PLA: Pre = 1848 ± 422.9; Pos = 1875 ± 450.1; ∆ = +1.4%, p = 0.402, g = 0.07) compared when they consumed placebo. In conclusion, the results of this investigation, for this specific sample and in our experimental conditions, creatine supplementation did not modify the body composition nor the maximum strength of the individuals, but it was efficient as a physiological ergogenic, in strength resistance, contributing to an increase in the amount of work done (total volume).