Eccentric Hamstring Strength and ACL Injury Risk in NCAA Division I Female Field Hockey Athletes

Anterior cruciate ligament (ACL) injuries remain a pervasive issue in female collegiate athletics, particularly in sports demanding frequent decelerations, cuts, and high-speed movements such as field hockey. Despite the high injury burden, limited research has investigated biomechanical and workload-based risk factors specific to NCAA Division I female field hockey athletes. This study aimed to evaluate the relationship between changes in eccentric hamstring strength and movement load metrics with changes in a composite ACL Risk Index. The sample included nine NCAA Division I female field hockey players who completed a 13-week offseason strength and conditioning program. Eccentric hamstring strength was measured using the NordBord Hamstring Testing System (Vald Performance, Newstead, Australia), while high-speed distance (HSD) and high-intensity decelerations (HID) were captured via Catapult Vector GPS units. Z-score transformations of HSD and HID changes were used to create an individualized ACL Risk Index. A standard multiple linear regression was performed to identify predictors of change in ACL Risk Index. Change in HID emerged as the only statistically significant predictor (β = .686, p = .028), underscoring the critical role of braking loads in modulating ACL injury risk. While changes in between-limb hamstring strength, defined as limb asymmetry (β = –.641, p = .117), and eccentric hamstring strength (β = .309, p = .383) did not reach statistical significance, both contributed to the overall variance explained by the regression model, indicating potential clinical relevance in predicting ACL risk changes. The overall model explained 83.8% of the variance in ACL Risk Index scores (R² = .838, p = .070), suggesting practical significance despite the small sample size. This study supports the integration of field-based strength assessments and wearable GPS technologies to identify modifiable risk factors in female athletes. Findings reinforce the importance of eccentric strength development and braking load management in ACL injury prevention strategies. Limitations included the small sample size, absence of inertial measurement data for cutting intensity, and reliance on secondary data collection. Future research should incorporate multi-site samples, longer-term injury tracking, and more granular biomechanical analysis to improve generalizability and predictive accuracy. Overall, this research contributes novel insights into sport-specific ACL risk profiling and strengthens the foundation for individualized injury mitigation strategies in strength and conditioning practice.