The Effect of Time of Day on Visual Reaction Time Performance in Boxers: Evaluation in terms of Chronotype

Kemal Kurak ¹ İsmail İLBAK ¹ Stefan Stojanović ² Ramazan Bayer ³ Yunus Emre İlbak ⁴ Tadeusz Ambroży ⁵ Krzysztof Kasicki ^6* Łukasz Rydzik ⁵ Wojciech Czarny ⁷

• ¹ Institute of Health Sciences, İnönü University, 44000 Malatya, Türkiye, Malatya, Türkiye
• ² Faculty of Sport and Physical Education, University of Niš, Niš, Serbia
• ³ Department of Physical Education and Sport Teaching, Malatya Turgut Ozal University, Malatya, Türkiye
• ⁴ Faculty of Sport and Physical Education, İnönü University, 44000 Malatya, Türkiye, Malatya, Türkiye
• ⁵ Institute of Sports Sciences, University of Physical Culture, 31-571 Kraków, Poland, Kraków, Poland
• ⁶ Department of Physiotherapy, Faculty of Health Sciences, Collegium Medicum, Andrzej Frycz-Modrzejewski Krakow University, Kraków, Lesser Poland, Poland
• ⁷ Institute of physical culture science, College of Medical Sciences, University of Rzeszow, Rzeszów, Poland

Considering the impact of individual differences on athletes performance, chronotype emerges as a crucial variable in training program design. Chronotype influences an individuals' ability to achieve peak physical and cognitive performance at different times of the day based on their biological rhythms. While numerous studies have explored the relationship between chronotype and physical performance, its effect on reaction time performance remains insufficiently investigated. In sports, where reaction time is a key determinant, such as in boxing, understanding this relationship could contribute to the personalization of training programs. In this context, the aim of this cross-sectional study was to examine how the visual reaction performance of active boxers varies at different times of the day based on their chronotypes. Twenty-four participants whose chronotypes were determined as morning type (M-type) and evening type (E-type) through the Morningness-Eveningness Questionnaire were included in this study. Participants, divided into two separate groups, M-type (n=12) and E-type (n=12), performed a visual reaction time (VRT) performance test at three different times of the day (morning: 09:00 hours, afternoon: 13:00 hours, and evening: 17:00 hours). Findings from the study revealed a statistically significant group x time interaction effect on VRT performance (p <0.01). As a result of this study, it was determined that boxers' VRT performance varies across different times of the day depending on their chronotypes. The findings indicate that M-type athletes experience a significant decline in VRT performance during the evening compared to the morning and afternoon hours. In contrast, E-type athletes demonstrate significantly better performance in the evening compared to the morning. In this context, it is recommended that coaches and exercise specialists consider the chronotype of athletes when designing training programs aimed at improving reaction time performance. Furthermore, to minimize the impact of time of day and chronotype on competition performance, it is suggested that M-type athletes engage in reaction time enhancement training during the morning hours, while E-type athletes should perform such training sessions in the evening, when their performance tends to peak.