Effect of Daily Social Media Use on Smartphones Before Training on Attack Efficiency and Repeated Vertical Jump Ability in Young Male Volleyball Players: A Randomized and Crossover Trial

This investigation observed the repeated effect of using social media on smartphones immediately before training sessions on attack efficiency (AE) and repeat-vertical jumping ability (RVJA) in young volleyball athletes. A crossover study involved 14 volleyball athletes (17.57 ± 0.65 years of age). For three weeks, the athletes participated in their training routines under two experimental conditions: using social media (SMA) and watching documentaries (DOC), both for 30 min before the training sessions. Before and after the three weeks, the athletes had their AE and RVJA evaluated. The AE test consisted of performing 6 attacks, with the total score obtained by adding the product of the score and the speed of each attempt. RVJA was assessed using the intermittent vertical jump test of four sets of 15 s (IJT₆₀), with the average heights of the best series of 15 s (H_peak) and the total time (H_mean) used for analysis. The visual analog scale revealed an increase in subjective mental fatigue for both conditions (p < 0.05), with SMA having higher levels compared to DOC (p = 0.02). There were improvements in AE for DOC compared to SMA (p = 0.03). No differences were found between the experimental conditions for Hpeak and Hmean. The results demonstrated that using social media on smartphones immediately before training sessions caused mental fatigue and impaired AE in young volleyball athletes.