Playing videogames or using social media applications on smartphones causes mental fatigue and impairs decision-making performance in amateur boxers.

This study aimed to analyze the effect of playing videogames and using social media applications on smartphones on decision-making and countermovement jump (CMJ) performance in amateur boxers. Twenty one boxers were enrolled in the study and were randomly assigned to all three experimental conditions [smartphone (30SMA), videogame (30VID), and control (CON)]. CMJ was measured before and 30-min after each experimental condition. The athletes ran simulated combat recorded for decision-making analysis. The boxers watched coaching videos (CON), used social media applications on smartphones (30SMA), and played video games (30VID) for 30 min just before the combat simulation. Both attack and defense decision-making performance were worse in both 30SMA and 30VID conditions compared to the CON condition (p = 0.001). Regarding CMJ, despite no condition effect (p = 0.96) been obtained, a time effect (p = 0.001) was observed; So, it was found a decrease in CMJ performance after all experimental conditions (p = 0.001), with no difference between them. Using social media applications on smartphones and playing video game impairs decision-making performance in amateur boxers, with no harms for CMJ performance.