Time of day effects on physical and judo-specific performance in young judo athletes
Kons, R. L., Saldanha da Silva Athayde, M., Segedi, I., Sertić, H., & Detanico, D. (2026). Time of day effects on physical and judo-specific performance in young judo athletes. Biological Rhythm Research, 1–16.
This study investigated the effects of diurnal variation on physical and judo-specific performance in post-pubertal competitive judo athletes. Fourteen athletes (6 females, 8 males) participated in a repeated-measures design, with assessments conducted in the morning, afternoon, and evening. Athletes performed the isometric handgrip strength test (HGS), the Judogi Grip Strength Test (JGST; isometric and dynamic modes), the Maximal Sprint Specific Judo Test (MSS), and a high-intensity interval exercise (HIIE) protocol. Ratings of perceived exertion (RPE) were recorded throughout the HIIE. Data were analyzed using a two-way mixed-model repeated-measures ANOVA with Bonferroni-adjusted post hoc tests, with a significance level of 5%. No significant time-of-day effects were observed for HGS or JGST outcomes (p > .05). However, MSS performance differed across the day (p < .001, η2 p = 0.153, large), with better performance in the morning and afternoon than in the evening (p < .002). Repetitions during the HIIE declined progressively across sets (p < .001), whereas RPE increased throughout the protocol and was higher in the evening (p < .001, η2 p = 0.597, large). These findings suggest that diurnal variation affects anaerobic performance and perceptual responses, but not isometric or grip-based strength measures in young judo athletes.
KEYWORDS: adolescents – anaerobic – performance – circadian rhythm – combat sports – chronotype – perceived exertion
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