Cooperative learning, a pedagogical approach emphasizing structured collaboration and mutual responsibility, has been associated with academic and social benefits, yet its influence on adolescents’ prosocial and antisocial behaviors remains underexplored. This study examined the relationships between cooperative learning, affective experiences, and social behavior in adolescent students. A total of 261 adolescent students (M = 13.06 years, SD = 0.86) from Greece participated in this cross-sectional study. Data were collected via questionnaires assessing perceptions of cooperative learning, enjoyment, vitality, and prosocial/antisocial behaviors toward teammates and opponents. Factor analyses confirmed the validity of the Greek versions of the instruments. Path analysis revealed that contextual elements of cooperative learning explained a significant proportion of variance in enjoyment and vitality, which in turn predicted prosocial behavior toward both teammates and opponents. Specifically, enjoyment and vitality were positively associated with prosocial orientations, whereas vitality negatively predicted antisocial behavior toward teammates. Unexpectedly, group reflection and heterogeneity emerged as negative predictors of enjoyment and vitality, while interaction showed marginal positive effects. Indirect effects indicated that cooperative learning dimensions influenced social behavior primarily through enjoyment and vitality. These findings suggest that positive affective states mediate the impact of cooperative learning on students’ social conduct in PE. Implications for practice highlight the importance of carefully designing cooperative structures to enhance enjoyment and vitality while fostering prosocial interactions during adolescence.

This study evaluated shoulder rotator muscle strength, conventional and functional external/internal rotation (ER/IR) strength ratios, and fatigue responses in competitive male artistic gymnasts, compared to a control group consisting of physical education (PE) students. Twenty-six participants were included: 13 competitive gymnasts (22.7 ± 2.3 years) and 13 PE students (22.6 ± 1.5 years), free of shoulder disorders. Shoulder rotator muscle strength was assessed isometrically and isokinetically (60°·s⁻¹ and 180°·s⁻¹) before and after a fatigue protocol comprising 50 maximal concentric internal and external rotations at 240°·s⁻¹. Gymnasts demonstrated significantly higher body mass-normalized peak torque than PE students across the key strength conditions. Before fatigue, conventional and functional strength ratios were generally comparable between groups. Following fatigue, condition-specific changes in ER/IR strength ratios were observed, with gymnasts generally maintaining their pre-fatigue values. Normalized peak torque progressively declined across the 50-repetition protocol in both groups, with no significant between-group difference in the pattern or rate of torque decline. Exploratory analyses of derived fatigue-related measures showed limited and condition-specific between-group differences. Overall, competitive gymnasts demonstrated greater shoulder rotator strength capacity than PE students, whereas the findings did not support a generalized between-group difference in fatigue-related responses. Comprehensive assessment of shoulder strength, ER/IR strength ratios, and fatigue responses may provide useful information for performance monitoring and individualized training.