Resumo:
The relevance of understanding how time of day impacts performance becomes even more evident considering that many athletes compete at varying times, which can affect their physical performance. Based on this, this study sought to explore how the time of day affects physical performance responses in Brazilian Jiu-jitsu (BJJ) athletes. Given the importance of circadian rhythms in athletic abilities, we aim to determine whether variations in performance occur at different times of the day (morning, afternoon, night) and whether these effects differ by sex. The methodology used in this research is quantitative as it is a research approach that combines the analysis of numerical and statistical data with the description, classification and interpretation of information. Nine male Jiu-Jitsu athletes participated in an evaluation, performing physical tests including: maximum handgrip strength; kimono grip strength; and a specific Jiu-Jitsu test at designated times. The data were presented as mean and standard deviation and an ANOVA with repeated measures was used to verify the differences between the different periods (morning, afternoon and night) considering the specific physical tests. The results showed better physical performance at night for most tests, including increased handgrip strength and superior performance in the specific Jiu-Jitsu test (p<0.005). This suggests that higher body temperatures at night improve muscle function and overall performance. The study highlights the importance of aligning training and competition schedules with the athlete's circadian rhythms to optimize performance. However, limitations such as sample size and environmental factors suggest the need for further investigations to confirm these effects and explore potential gender-specific responses.
