Introduction: Football's anaerobic demands are a key physiological factor in player performance, likely varying throughout the day and affecting competition outcomes (Sabzevari Rad et al., 2021). However, most studies on time-of-day (TOD) effects have overlooked young athletes, despite increasing trends in early sports specialization (Myer et al., 2015). The present study aimed to investigate the effect of different times of day (TOD) on various aspect of maximal short-term physical performance among adolescent football players.

Methods: In a randomized order, 19 adolescent male football players with neither chronotype (age: 14.58 ± 0.7y) were tested at four different TOD sessions at (08:00h, 11:00h, 15:00h, and 18:00h) with an in-between recovery period of ≥48 h. During each test session, the oral temperature (OT), medecine ball throw test (MDT), 5m sprint test (5m-T), 20m sprint (20m-T), illinois agility test (IAT), and illinois agility test with ball (IAT-B) were evaluated.

Results: While OT had significantly increased at 15:00h and 18:00h (both p< 0.001) compared to 08:00h, no significant difference was detected at 11:00h (p > 0.05). Post hoc test revealed that compared to 08:00h, (MDT, 5m-T, 20m-T, IAT, and IAT-B) significantly increased at 11:00h (p < 0.001, p < 0.001, p < 0.001, p < 0.01, and p < 0.001 respectively), 15:00h (p < 0.001, p < 0.001, p < 0.01 , p < 0.001, and p < 0.05 respectively,) and 18:00h (all p < 0.001). Likewise, no significant difference was revealed between 11:00h and 15:00h (all p > 0.05). When compared to 18:00h, a significant difference was demonstrated at 11:00h (p < 0.05; p < 0.01; p < 0.05; p < 0.05 respectively) and 15:00h (p < 0.01, p < 0.001, p < 0.001, and p < 0.001 respectively) slots.

Discussion: The current outcomes align with a recent meta-analysis (Ravindrakumar et al., 2022) that revealed that late afternoon and early evening (between 16:00h and 07:30h) are most favorable TOD for short-term maximal physical performance. Moreover, it has been repeatedly documented that acrophase is often detected in the late afternoon (Souissi et al., 2008), and that short-term maximal performance exhibits circadian and diurnal fluctuation with amplitudes ranging from 2 to 26% (Facer-Childs & Brandstaetter, 2015).

Conclusion: In summary, there was a significant effect of TOD on the maximal short-term physical performance. The current results highlight the superiority of a late afternoon slot (18:00h) to complete optimal maximal performance comparing to morning (08:00h, 11:00h) and early afternoon, (15:00h), which could affect whole athletic performance. In practice, athletes should favour a late afternoon slot to train as this allows them to achieve the best level of performance.

References

Facer-Childs, E., & Brandstaetter, R. (2015). The impact of circadian phenotype and time since awakening on diurnal performance in athletes. Current Biology: CB, 25(4), 518–522. https://doi.org/10.1016/j.cub.2014.12.036

Myer, G. D., Jayanthi, N., Difiori, J. P., Faigenbaum, A. D., Kiefer, A. W., Logerstedt, D., & Micheli, L. J. (2015). Sport Specialization, Part I: Does Early Sports Specialization Increase Negative Outcomes and Reduce the Opportunity for Success in Young Athletes? Sports Health: A Multidisciplinary Approach, 7(5), 437–442. https://doi.org/10.1177/1941738115598747

Ravindrakumar, A., Bommasamudram, T., Tod, D., Edwards, B. J., Chtourou, H., & Pullinger, S. A. (2022). Daily variation in performance measures related to anaerobic power and capacity: A systematic review. Chronobiology International, 39(3), 421–455. https://doi.org/10.1080/07420528.2021.1994585

Sabzevari Rad, R., Mahmoodzadeh Hosseini, H., & Shirvani, H. (2021). Circadian rhythm effect on military physical fitness and field training: A narrative review. Sport Sciences for Health, 17(1), 43–56. https://doi.org/10.1007/s11332-020-00692-w

Souissi, N., Souissi, M., Souissi, H., Chamari, K., Tabka, Z., Dogui, M., & Davenne, D. (2008). Effect of time of day and partial sleep deprivation on short-term, high-power output. Chronobiology International, 25(6), 1062–1076. https://doi.org/10.1080/07420520802551568