Association between youth athletes' sports specialization and injuries: a systematic review and meta-analysis.
INTRODUCTION: The purpose of this study was to conduct a systematic review and meta-analysis to examine the specialization-injury relationship, and explore whether the specialization-injury relationship is moderated by study design, sport type, age, sex, and injury measurement type, injury mechanism, and anatomical location. METHODS: We searched eight databases by related keywords and assessed the quality of the included studies using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies and the Newcastle-Ottawa Scale. The Comprehensive Meta-Analysis (CMA) statistical software 3.7 examined heterogeneity, sensitivity, publication bias, overall effect size of specialization-injury relationship, and moderation effects. This review was prospectively registered in PROSPERO (CRD420251233318). Searches were conducted in eight electronic databases from inception to March, 2026. RESULTS: The 15 included studies showed moderate heterogeneity, stable sensitivity analyses, and no publication bias. The overall odds ratio of the sports specialization-injury relationship was 2.00 (95% confidence interval [1.58-2.55], p < .001). Moderation analyses indicated that sport type significantly influenced the specialization-injury relationship, whereas no significant moderation effects were observed for study design, sex, age, injury measurement type, injury mechanism, and injury anatomical location. CONCLUSIONS: The findings indicate a positive association between sport specialization and injury risk among youth athletes, with variation across sport participation contexts. Specifically, athletes in both contact and non-contact sports demonstrated higher pooled odds of injury than those involved in multiple sports. Although the evidence is heterogeneous and should be interpreted with caution, these findings highlight the potential role of diversified sport participation in relation to injury.