Research Review: Evening Training Improves Grip Strength and BJJ-Specific Performance Without Increasing Perceived Exertion in Both Male and Female Athletes  

By Jackson Mann

BLUF (Bottom Line Up Front)

Brazilian Jiu-Jitsu (BJJ) athletes demonstrated better physical performance in the evening compared to the morning and afternoon, particularly in grip strength and sport-specific tests. However, these performance improvements occurred without corresponding differences in perceived exertion or between sexes. This suggests that aligning BJJ training with athletes’ circadian rhythms—specifically in the evening—may enhance training effectiveness.

Purpose of the Study

The study aimed to examine whether the time of day influences physical performance and perceptual responses in trained BJJ athletes. Considering the impact of circadian rhythms on physiological capacity, researchers also explored whether these time-of-day effects differed between male and female athletes. The central question was whether performance in strength and BJJ-specific tasks varied meaningfully depending on whether athletes trained in the morning, afternoon, or evening.

Methods

Twenty-three Brazilian Jiu-Jitsu (BJJ) athletes—14 men and 9 women—participated in a repeated-measures experimental design aimed at assessing how time of day influences physical and perceptual performance. Each participant completed three testing sessions, each conducted at a different time of day: morning (10:00–11:00), afternoon (14:00–15:00), and evening (18:00–19:00). 

During each session, athletes performed a battery of physical tests. The Maximal Isometric Handgrip Strength Test (HGS) was used to assess peak grip force, an essential attribute for grappling. The Kimono Grip Strength Endurance Test (KGST) was designed to evaluate sustained grip endurance under sport-specific conditions, simulating the repeated gripping demands of live BJJ training. Additionally, athletes completed a BJJ-Specific Test (BJJST), tailored to mimic the technical and physical workload typical of sparring scenarios, integrating both skill and conditioning components.

To assess perceptual responses, the Rating of Perceived Exertion (RPE) was recorded prior to the BJJST at each session. This allowed researchers to examine whether time-of-day effects on performance were accompanied by shifts in athletes’ subjective sense of effort or fatigue.

Key Findings

Athletes consistently performed better in the evening across all primary physical tests. Specifically, both male and female participants showed greater handgrip strength (HGS), improved grip endurance in the KGST, and better output in the BJJ-specific test (BJJST) during the 18:00–19:00h session (p < 0.05). 

Importantly, there were no significant differences in perceived exertion (RPE) between morning, afternoon, and evening sessions (p > 0.05), indicating that although athletes performed better in the evening, they did not feel significantly more or less taxed at any time. Additionally, no sex-based differences were observed in performance trends across the day (p > 0.05), suggesting that both male and female athletes respond similarly to circadian influences in BJJ contexts.

Interpretation & Significance

The data support the conclusion that evening training may be ideal for optimizing physical performance in BJJ athletes, particularly for tasks involving grip strength and endurance—key components of success in the sport. The absence of differences in RPE across time points implies that these gains are not the result of athletes simply “feeling better” in the evening, but reflect true physiological enhancements likely driven by circadian modulation of strength and motor output.

From a practical standpoint, these findings encourage BJJ coaches and athletes to consider the time of day when scheduling high-intensity or technical training sessions. Training in alignment with circadian peaks may yield better immediate performance and improve the quality of stimulus over time—contributing to more efficient skill acquisition and athletic development.

Conclusions

Time of day has a clear impact on physical performance in BJJ athletes, with the evening offering the most favorable window for strength and sport-specific output. Since perceived effort and sex did not influence these effects, training programs could be optimized by aligning peak sessions with evening hours, taking full advantage of the body’s natural performance rhythms without added fatigue or differential planning for male and female athletes.

Source

1. Kons, R., Santos, G., Borges, M. L. B., Cintra de Sousa, P. H., & Detanico, D. (2025). Time-of-day effects on physical performance and perceptual responses in Brazilian Jiu-Jitsu athletes. Chronobiology International, 42(1), 147–154.