Comparative Effectiveness of Exercise Interventions for Hamstring Injury Prevention in Football Players: A Systematic Review and Network Meta-analysis.
BACKGROUND: Hamstring strain injury is a leading time-loss injury in football, yet trials have evaluated diverse exercise-based prevention programs with limited direct head-to-head evidence. This systematic review and network meta-analysis aimed to compare the effectiveness of exercise-based interventions for preventing hamstring injuries in football players using exposure-adjusted incidence rate ratios. METHODS: We conducted a PRISMA-aligned systematic review and random-effects network meta-analysis of randomized controlled trials in football players comparing exercise-based interventions to prevent hamstring injuries. Searches covered PubMed, Cochrane Library, Embase and Web of Science from inception to January 5, 2026. Interventions were modeled as separate nodes (Nordic hamstring exercise [NHE], FIFA 11, FIFA 11 + , FIFA 11 + Kids, bounding exercise program [BEP], usual training). The primary effect measure was incidence rate ratio (IRR) versus usual training, with ranking by P-scores; exploratory subgroup analyses were conducted by sex-restricted male-only evidence and age group. RESULTS: Eleven randomized controlled trials involving 9,282 participants were included. The network was connected but largely star-shaped, with most evidence comparing active interventions against usual training and no direct active-active comparisons. FIFA 11 + showed the most consistent exposure-adjusted association with reduced hamstring injury incidence versus usual training (IRR = 0.55, 95% CI 0.31-0.98; P-score = 0.84). FIFA 11 + Kids showed a favorable but imprecise estimate, whereas NHE showed a modest non-significant reduction and FIFA 11 and BEP showed no clear benefit. Male-only findings were broadly consistent with the primary analysis. Age-stratified analyses suggested that the apparent hierarchy was not fully identical across age strata, but subgroup networks were sparse and exploratory. RoB 2 judged three studies as high risk and eight as having some concerns; no trial was judged as overall low risk. Between-study heterogeneity was substantial, and treatment rankings were, therefore, interpreted cautiously. CONCLUSIONS: In this IRR-based network meta-analysis, FIFA 11 + showed the most consistent exposure-adjusted association with reduced hamstring injury incidence compared with usual training. However, certainty across the primary comparisons ranged from low to very low because of clinical and methodological heterogeneity, sparse direct evidence for several nodes, reliance on indirect active-active comparisons, substantial between-study heterogeneity, and moderate-to-high risk of bias across the included studies. The treatment hierarchy should, therefore, be interpreted as a low-to-very-low-certainty, population-level summary rather than as a basis for firm recommendations. Further well-reported, age- and population-specific head-to-head trials with consistent exposure, injury-definition, adherence, and intervention-dose reporting are needed. Registration Systematic review registration PROSPERO (CRD420251243576).