A one year prospective study on ankle stability and landing technique: the occurrence of ankle and knee injuries in elite ball team athletes
Background: In team sports lower extremity injuries account for more than 50% of all injuries, indicating the importance of early detection of athletes at risk. Objective: To investigate the predictive value of ankle stability and landing technique at baseline for ankle and knee injury occurrence during the consecutive season in indoor team sport athletes. Design: A prospective longitudinal cohort study. Setting: (Sub-)elite level basketball, korfball or volleyball athletes participated. Participants: Out of fifty-eight athletes forty-two athletes (age:22.2±3.9yr,height:184.5±11.8cm,mass:79.0±15.2kg) met the inclusion criteria; being ≥eighteen years, performed baseline measurement and completion of consecutive season. Interventions (assessment risk factors): Athletes performed the Single-Leg Jump-Landing (SLJL) test and the Landing Error Scoring System (LESS) Jump, a jump-landing-rebound task, at baseline. SLJL test resulted in a dynamic stability index (DSI) in medial-lateral (ml), anterior-posterior (ap) and vertical (v) direction for frontal, diagonal and lateral jump direction. High DSI indicates poor stability. The LESS determines an athlete’s landing technique; high score represents poor landing technique. Main Outcome measurements: Ankle and knee injuries were registered according to the FIFA registration system. Results: Nine ankle injuries and seven knee injuries were reported. Athletes that reported an ankle injury scored a significant (p≤0.05) higher DSI compared to non-injured athletes in diagonal ap (0.072±0.01 vs 0.066±0.01), diagonal v (0.350±0.06 vs 0.305±0.05) and lateral ap (0.057±0.01 vs 0.047±0.01) direction. Athletes that reported a knee injury scored a non-significant higher LESS score (7.46±1.38) compared to non-injured athletes (6.20±2.0). Conclusions: Athletes who sustained an ankle injury during the season showed higher DSI at baseline. Athletes with a knee injury showed tendency toward poorer landing technique. Both tests seem feasible to screen athletes at baseline giving insight in high-risk athletes. Prevention programs could be implemented preventing these athletes from sustaining an injury.