Introduction: Young female athletes participating in sports involving running, pivoting, jumping and landing are at increased risk of sustaining anterior cruciate ligament (ACL) injury. Knee valgus loading plays a critical role in the mechanism of ACL injury. So far, however, few prospective studies have investigated biomechanical risk factors of ACL injury, and only one study has found an association between knee valgus loading and future ACL injury. Thus, the purpose of the study was to investigate the biomechanical risk factors of ACL injuries in young female athletes from basketball and floorball. Methods: A total of 171 female basketball and floorball players (aged 12-21) participated in a vertical drop jump (VDJ) test using 3D motion analysis. The following biomechanical variables were analyzed in six separate Cox regression models: 1) knee valgus angle at initial contact (IC), 2) peak knee abduction moment, 3) knee flexion angle at IC, 4) peak knee flexion angle, 5) peak vertical ground reaction force (GRF), and 6) medial knee displacement (MKD). We registered new ACL injuries and players` match and training exposure until April 2014 (range, 1-3 years). Cox regression models were used to calculate hazard ratios (HRs) and 95 % confidence intervals (CIs). Results: Fifteen new ACL injuries occurred during the study period (0.2 injuries / 1 000 player hours). Peak knee flexion angle (HR for 10 unit change 0.47; 95 % CI 0.27 - 0.81) and peak vertical GRF (HR for 100 unit change 1.31; 95 % CI 1.12 - 1.54) were associated with increased risk for ACL injury. Knee valgus angle at IC (HR for 10 unit change 1.89; 95 % CI 0.69 - 5.00), knee flexion angle at IC (HR for 10 unit change 1.31; 95 % CI 0.69 - 2.48), peak knee abduction moment (HR for 10 unit change 1.12; 95 % CI 0.89 to 1.43), and medial knee displacement (HR for 10 unit change 1.95; 95 % CI 0.72 - 1.24) were not significantly associated with ACL injuries. Of the adjustment factors, players` lower height (HR 0.85; 95 % CI 0.74 to 0.98), and playing at adult league level (HR 4.85; 95 % CI 1.14 to 20.62) were risk factors of ACL injury. Age, weight, sport and previous ACL injury were not significantly associated with ACL injuries. Discussion: This prospective study showed that landing with decreased knee flexion and high vertical ground reaction force were associated with increased risk of ACL injury in young female basketball and floorball players. Our study did not find any significant associations between frontal plane biomechanics and future ACL injury. Based on these findings, preventive training should include neuromuscular training not only to avoid valgus movement but also to avoid stiff landings.
© Copyright 2016 21st Annual Congress of the European College of Sport Science (ECSS), Vienna, 6. -9. July 2016. Julkaistu Tekijä University of Vienna. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator