Modifiable risk factors for lower-extremity injury: a systematic review and meta-analysis for the Female, Woman and Girl Athlete Injury Prevention (FAIR) consensus

Objective Examine potentially modifiable risk factors (MRFs) for female/woman/girl athletes’ lower-extremity injuries. Design Systematic review with meta- or semiquantitative analyses and Grading of Recommendations, Assessment, Development and Evaluation. Data sources MEDLINE, CINAHL, APA PsycINFO, Cochrane Systematic Review Database, CENTRAL, SPORTDiscus, EMBASE, ERIC searched 30 October or 23 November 2023. Eligibility Primary data studies with comparison group(s) assessing the association of MRFs for sport-related lower-extremity injury(s) with ≥1 female/woman/girl per study group. Results Across 195 studies (n=115; 58.9% female/woman/girl-specific estimates) including 1 525 662 participants (2.4% females/women/girls), eight injury outcomes were assessed (n=75 general lower-extremity, n=3 groin, n=6 hip, n=17 thigh, n=88 knee, n=17 lower-leg, n=27 ankle, n=9 foot). Sixty-six MRF categories were identified. Substantial heterogeneity in MRFs and injury outcomes exists, with high risk of bias present in 37.4% of studies. Considering female/woman/girl specific estimates, we performed meta-analyses for 10 MRFs (body mass, x (BMI), weekly training distance, muscle strength, artificial turf, off-season plyometric training, readiness to return-to-sport, single-leg hop asymmetry, vertical drop jump peak knee flexion angle and ground reaction force) and semiquantitative analyses for 26 MRFs for a variety of injuries. Meta-analyses suggest no association between any lower-extremity strength outcome (g=0.01, 95% CI −0.11 to 0.14; I 2 =37.3%; very low certainty evidence) or artificial turf (Incidence Rate Ratio=0.97, 95% CI 0.88 to 1.07; I 2 =2.4%; low certainty evidence) and various lower-extremity injuries. Higher body mass (g=0.19, 95% CI 0.00 to 0.38; I 2 =71.7%) and/or BMI (g=0.22, 95% CI 0.09 to 0.36; I 2 =37.0%) are associated with several lower-extremity injuries (very low certainty evidence). Conclusion This review synthesises a large body of exploratory research, exposes important knowledge gaps and provides a foundation for understanding MRFs for female/woman/girl athlete lower-extremity injuries. PROSPERO registration number PROSPERO CRD42024486715.