Physical Activity, Psychological Resilience, and Non-Suicidal Self-Injury Among Male College Students: A Cross-Sectional Study

Background/Objectives: Non-suicidal self-injury (NSSI) is an important mental health concern among college students, yet evidence regarding behavioral and psychological correlates of NSSI among male students remains limited. This study examined the cross-sectional associations among physical activity (PA), psychological resilience (PR), and NSSI in male college students and explored heterogeneity in joint PA–PR patterns. Methods: A cross-sectional survey was conducted among 2567 male college students from one university in Jiangxi Province, China. PA, PR, and NSSI were assessed using the Physical Activity Rating Scale-3, the 10-item Connor–Davidson Resilience Scale, and 10 behavioral-frequency items from the Ottawa Self-Injury Inventory, respectively. Pearson correlations, covariate-adjusted regression analyses, bootstrap analysis of the statistical indirect association, sensitivity analyses, and latent profile analysis (LPA) were performed. Results: PA was positively associated with PR (r = 0.627, p < 0.001), whereas PA and PR were negatively associated with NSSI (r = −0.259 and −0.292, respectively; both p < 0.001). After adjustment for all measured demographic characteristics, PR statistically accounted for part of the negative association between PA and NSSI (indirect effect = −0.133, 95% bootstrap CI [−0.164, −0.102]). The NSSI model explained 9.8% of the variance. Past-year NSSI was reported by 35.41% of participants. LPA identified two predominantly level-based profiles: Low PA–Low PR and High PA–High PR. Participants in the Low PA–Low PR profile reported significantly higher NSSI scores than those in the High PA–High PR profile. Conclusions: Higher PA and PR were associated with lower NSSI among male college students, and PR statistically accounted for part of the cross-sectional PA–NSSI association. The two PA–PR profiles also differed in NSSI levels. These findings indicate that PA and PR are relevant correlates of NSSI, although their temporal and causal relationships require further investigation.