Physical Activity, Body Mass Index, and Bullying in Higher Education: A Comparative Analysis of Students with and Without Structured Sports Training.

Background/Objectives: Organized physical activity is frequently considered a protective factor against bullying behaviors, yet evidence within the university context remains limited. This study investigates the relationships between physical activity levels, body mass index (BMI), and involvement in traditional and digital bullying, taking into account the differences between students with and without structured sports training. Methods: A total of 2767 first-year students from Transylvania University of Brașov participated. The sports group (n = 161; 65 females, 96 males) was compared to the non-sports group (n = 2606; 1472 females, 1134 males). Instruments included the Physical Activity Questionnaire for Adolescents (PAQ-A), validated scales for traditional and cyberbullying and victimization, and BMI calculation. Statistical analyses involved t-tests (two-tailed), 2 × 2 factorial ANOVA, and sex-stratified multiple linear regressions. Results: Students with sports training reported higher physical activity (PAQ-A 4.2-4.6), lower BMI, and lower bullying involvement (traditional ≈ 14-21% vs. ≈32%; cyber ≈ 8-17% vs. ≈25%). Group differences were large for physical activity (Hedges' g ≈ 1.5) and moderate for BMI and bullying (g ≈ 0.68-0.96; point-biserial r² ≈ 3-4%). ANOVA showed sports status main effects (partial η_p² ≈ 4-5% for bullying/BMI; ≈20% for PAQ-A). In regressions, sports status (B = -0.30 to -0.44) and physical activity (B = -0.22 to -0.32) predicted lower aggression/victimization, whereas BMI showed positive associations (B = 0.11 to 0.18) (all p < 0.001). Sex × sports interactions were significant for PAQ-A and for traditional and cyber-victimization. Conclusions: Structured physical activity contributes to reducing the risk of bullying involvement and supports better psychosocial adjustment among students. These findings underscore the educational and preventive potential of university sports programs.