Comparing Touch-Limited and Free-Play 4v4 Small-Sided Games (SSGs)

This study aimed to compare acute serum BDNF and cognitive performance following touch-limited versus free-play 4v4 small-sided games (SSGs) in male soccer players. This randomized crossover controlled trial aimed to examine the acute effects of touch-limited (SSGr) vs free-play (SSGf) 4v4 SSGs on serum brain-derived neurotrophic factor (BDNF), blood lactate levels and executive function performance in male soccer players. All participants completed the two conditions in a randomized and counterbalanced manner. To ensure balanced exposure, they were assigned to one of two groups (n=16), each following a distinct condition. A seven-day interval separated each session to reduce residual physiological or cognitive effects. The trial protocol was developed in line with Consolidated Standards of Reporting Trials guidelines, including for within-subject designs and non-pharmacological interventions. Participants were blinded to the study hypothesis. Teams were formed based on the coach's assessment of the players' technical, tactical, and physical abilities. To minimize differences in player's maximum oxygen consumption (VO2 max) level estimated from the 30-15 Intermittent Fitness Test (30-15 IFT) were also taken into account. The SSG sessions were conducted at 10.00-12.00 to have similar chronobiological characteristics on a natural grass pitch during the off-season period under the supervision of A-licenced coaches to ensure consistency and adherence to protocol. All players continued their routine off-season training program, which involved three training sessions (strength, aerobic activity, aerobic running) per week. Players were advised to avoid strenuous exercise within 48 h, be prohibited from drinking alcohol or coffee within 24 h, and have at least 7-8 h of sleep before the intervention. During this study, the players were instructed to maintain their dietary habits and general lifestyle. During the first visit, participants' resting heart rate was recorded.