Is Cumulative Load Associated with Injuries in Youth Team Sport? A Systematic Review

BACKGROUND: High cumulative external and internal load may predispose athletes to increased risk for injury across a variety of sports, competition levels, and age groups. However, evidence of an association between cumulative load and injury in youth sport remains inconclusive. The objective of this study was to determine the current evidence for cumulative load and injury risk relationships in youth team sport through a systematic review of the existing literature. METHODS: A systematic review of the literature was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Literature searches were conducted in PubMed, Web of Science, SCOPUS, and CINAHL for relevant articles published between January 2010 and April 2021. The authors conducted independent review and quality assessment of the eligible studies. Eleven articles evaluating youth (less than 18 years old) team sport were included for qualitative synthesis. RESULTS: Fifty-nine percent (n = 39/66) of the relationships assessed revealed an association between cumulative load and injury across the team sports studied, including the presence of load–injury associations in 84% (n = 16/19) of assessments in youth soccer. Of those relationships where an association was present, 79% (n = 31/39) were positive associations between cumulative load and injury. Risk of bias assessment scores ranged from three to six out of seven possible (median = 5) for cohort studies and from four to seven out of 10 possible (median = 5.5) for cross-sectional studies. CONCLUSIONS: There is some evidence for a positive association between load and injury in youth team sport. Youth soccer was the most studied team sport, and a substantial number of positive load–injury associations were reported. Current evidence lacks consistency in the measures and metrics used in defining load–injury relationships. Trial Registration PRISMA ID - CRD42020203622. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40798-022-00516-w.