Acute psychological responses to formal and small-sided volleyball games in male youth athletes: an exploratory repeated-measures study.

Introduction: Small-sided games are frequently used in youth sport training, yet their acute psychological effects in volleyball remain insufficiently described. This study examined whether formal games (6 vs. 6) and small-sided games (3 vs. 3) were associated with distinct short-term responses in anxiety, mood, affective valence, enjoyment, perceived recovery, and perceived exertion among male youth volleyball athletes. Methods: Thirty male athletes aged 14-18 years completed repeated training sessions under two game formats during the pre-competitive period. Psychological and perceptual measures were obtained before and/or after each session, depending on the outcome assessed. Generalized Estimating Equations were used to examine condition, moment, and condition × moment effects. Given the sample size, the nonrandomized repeated-measures design, and the fixed sequence of conditions, the findings should be interpreted as exploratory, as condition effects cannot be fully separated from order and time-related influences. Results: State anxiety increased from pre- to post-session, irrespective of game format. Among the mood-related outcomes, only tension demonstrated a statistically robust condition × moment interaction after false discovery rate correction, with less favorable post-session responses in the 3 vs. 3 format. Depression, fatigue, and confusion increased, and vigor decreased from pre- to post-session regardless of condition. Affective valence, perceived recovery, and perceived exertion did not differ between formats. Although anger and enjoyment showed condition-related differences in the unadjusted analyses, these findings did not remain statistically robust after correction for multiple comparisons. Discussion: In this exploratory sample of male youth volleyball athletes, formal and small-sided games produced broadly similar acute psychological responses across most outcomes. The most robust condition-related finding was higher post-session tension in the small-sided format, whereas the unadjusted findings for anger and enjoyment should be interpreted with caution, as they did not remain statistically robust after false discovery rate correction. These findings suggest that different game formats may be associated with specific short-term emotional experiences during training, but larger, better-controlled studies are needed before drawing definitive conclusions about their implications for mental health-related outcomes in youth sport.