1. Introduction
Soccer is a team sport that requires players to process a significant amount of information quickly and respond with both speed and accuracy to the ever-changing demands of the game. As such, success in soccer depends not only on physical attributes but also on cognitive abilities such as perception and decision-making. The aim of the current study was to investigate the acute effects of caffeine ingestion on Stroop test performance before and after repeated small-sided games (SSG) in professional soccer players. Twelve professional male soccer players (29 ± 4.1 years; 78.1 ± 7.7 kg body mass) participated in this study. A randomized crossover double-blind placebo-controlled trial was used. Caffeine (5 mg.kgExecutive function encompasses a range of cognitive abilities that are essential for goal-directed behaviour. These cognitive processes include working memory, planning, problem-solving, sustained attention, inhibition, and cognitive flexibility. [Dietary supplements are used by athletes at all levels of sport with the ultimate aim of improving performance and recovery [For example, Hogervorst et al. [Another important aspect to consider pertains to the doses required to elicit positive effects on both physical and cognitive performance. Currently, there is ambiguity regarding whether the doses of caffeine necessary to enhance performance are equivalent to those needed for improved cognitive function. Furthermore, it remains uncertain whether higher doses of caffeine have the potential to enhance physical performance while simultaneously impairing cognitive function. To the best of our knowledge, the effects of acute caffeine ingestion on executive function in soccer players were not investigated. Therefore, the aim of the present study was to examine the effects of consuming a moderate dose of caffeine (5 mg.kg