This study investigated how the time of day affects physical performance and perceptual responses in Brazilian Jiu-Jitsu (BJJ) athletes. Given the significance of circadian rhythms on athletic capabilities, we aimed to determine whether performance variations occur across different times of the day (morning, 10:00-11:00h
afternoon, 14:00-15:00h
and evening, 18:00-19:00h) and if these effects differ by sex. In total, 23 BJJ athletes (9 females, 14 males) participated in this study. The athletes performed physical tests including the maximal isometric handgrip strength test (HGS), Kimono Grip Strength Endurance Test (KGST), and a BJJ-specific test (BJJST) in the morning, afternoon, and evening. Perceptual responses (RPE) were also collected before the BJJST. Results showed enhanced physical performance in the evening for most tests, including increased HGS and superior performance in the KGST and BJJST for both sexes (