Ankle flexibility asymmetry as a predictor of ankle injury in college soccer players: A prospective cohort study

Background: Ankle injuries represent a significant burden in soccer, with intrinsic risk factors including proprioception, flexibility, and body mass index (BMI) potentially contributing to long-term disability. Understanding these factors is crucial for injury prevention strategies. Objectives: To determine the association of intrinsic risk factors (flexibility, proprioception, and BMI) with ankle injuries in college soccer players. Methods: This prospective cohort study included 62 male college soccer players aged 18-25 years. Baseline assessments included BMI measurement, ankle flexibility using the Weight-Bearing Lunge Test (WBLT), and proprioception using the Star Excursion Balance Test (SEBT). Participants were followed up monthly for six months, with ankle injuries being recorded using a standardised injury report form. Binary logistic regression analysis was performed using SPSS. Results: During the six-month follow-up period, 12 participants (19.4%) sustained ankle injuries. Binary logistic regression revealed that flexibility asymmetry was a significant predictor of ankle injury (p=0.045, OR=0.000164, 95% CI: 0-0.811). Proprioception showed borderline significance (p=0.051, OR=2.18, 95% CI: 0.998-4.761). BMI was not significantly associated with ankle injuries (p=0.082). Independent t-tests demonstrated significant differences in flexibility between injured and non-injured players for both right (p<0.001) and left (p<0.001) ankles. Conclusion: Flexibility and proprioception asymmetries at the ankle joint are significant predictors of ankle injuries in college soccer players. These findings support the implementation of flexibility training as a preventive measure in this population.