Background: School bullying represents a critical global public health issue among adolescents. Although existing evidence suggests physical activity (PA) may reduce bullying risk, longitudinal data on bidirectional associations and gender-specific variations remain limited. This study employed a cross-lagged panel model (CLPM) to investigate the temporal dynamics between PA and school bullying (SB) and examine gender-moderating effects. Methods: A cohort of 577 middle school students (294 boys, 283 girls; mean age = 14.31 ± 2.1 years) from seven schools across Wuhan, Shijiazhuang, and Chengdu completed three-wave longitudinal assessments over 9 months (September 2024–March 2025). Validated instruments included the School Bullying Scale (SBS) and Physical Activity Rating Scale (PARS). The CLPM analysis evaluated bidirectional predictive pathways, with gender-stratified multi-group comparisons. Results: Significant bidirectional negative associations emerged: (1) PA at T1/T2 predicted reduced SB at T2/T3 (β = −0.14 to −0.26, p < 0.001). (2) SB at T1/T2 predicted decreased PA at T2/T3 (β = −0.27 to −0.38, p < 0.001). (3) Gender significantly moderated these relationships, with PA conferring stronger protective effects against subsequent SB in males (β = −0.35 vs. −0.21 for PA→SB paths). Conversely, SB triggered earlier and more pronounced PA reductions in males (β = −0.42 vs. −0.29 for SB→PA paths). Conclusions: PA and SB demonstrate stable bidirectional negative associations in adolescents, with significant gender divergence. Males exhibit greater resilience to bullying through PA engagement but heightened vulnerability to PA reduction post-victimization. These findings underscore PA-based interventions as promising bullying mitigation strategies, necessitating gender-tailored implementation approaches.

Objective: This study aimed to construct a theoretical structure of the Sense of Learning Gain (SLG) for Sports Science postgraduates, develop a standardized measurement instrument, identify its key influencing factors, and propose pathways for enhancement. Methods: Utilizing a stratified sampling method, postgraduate students from multiple provinces across China participated in an online questionnaire survey, divided into a pilot study ( n = 302) and a formal survey ( n = 306). The initial scale was developed through literature analysis and interviews. Exploratory Factor Analysis (EFA) was employed to determine the scale structure, followed by Confirmatory Factor Analysis (CFA) to test the model fit. Reliability and validity were assessed using Cronbach’s α , Composite Reliability (CR), and Average Variance Extracted (AVE). Group differences were analyzed via independent samples t -tests and ANOVA, and a Structural Equation Model (SEM) was constructed to examine the influencing factors. Results: (1) The final SLG Scale for Sports Science Postgraduates comprises 25 items across three dimensions: “Tangible Gains,” “Capability Enhancement,” and “Emotional Fulfillment,” with a cumulative variance explanation rate of 57.253%. (2) The formal scale demonstrated excellent reliability (Total α = 0.928; Subscale α : 0.753–0.925) and good structural validity (CFA: χ ² / df = 2.644, RMSEA = 0.076, CFI = 0.911). (3) The overall level of SLG was relatively high (M = 3.44, SD = 0.823), with the “Tangible Gains” dimension scoring highest (M = 3.82, SD = 1.074). Significant gender (male > female, p < 0.05) and grade differences (first-year > second/third-year, p < 0.01) were observed. (4) The SEM revealed that “School Resources” ( β = 0.457), “Social Environment” ( β = 0.322), “Interpersonal Support” ( β = 0.226), and “Personal Growth” ( β = 0.196) all had significant positive effects on the SLG. Conclusion: The developed scale proves to be a reliable and valid tool for measuring the SLG among Sports Science postgraduates in China. The SLG is co-influenced by multi-level factors, and targeted optimization of the social environment, interpersonal support, school resources, and individual development can effectively enhance it.

Introduction: Internalized weight stigma may be associated with compulsive exercise through body-related self-conscious emotions and negative body image, but the underlying pathways and individual-level heterogeneity remain unclear. Methods: This cross-sectional study included 513 college students. Structural equation modeling was used to examine direct and indirect associations, and latent profile analysis was used to identify subgroups of body-related distress. Results: Internalized weight stigma was positively associated with compulsive exercise. Body shame, body guilt, and negative body image state showed significant indirect associations, including two significant serial mediation pathways. Three profiles were identified: low, moderate, and high distress. The high-distress profile had the highest compulsive exercise score. Discussion: These findings identify possible psychological pathways and a subgroup with jointly elevated distress. Because the study was cross-sectional, causal conclusions cannot be drawn.