Analyze the Differential Rates of Anterior Cruciate Ligament Injuries Between Men and Women by Biomechanical Study of Single-Leg Landing in Badminton

Background In female badminton players, certain landings are associated with injury to the anterior cruciate ligament (ACL). However, the kinematic and kinetic changes of the landing leg and the effects of risky posture on ACL injuries among female vs male badminton players are still unknown. We hypothesized that female players land with a significantly higher knee valgus angle and moment compared to male players during single-leg landings in badminton. Methods Ten male and ten female badminton players were enrolled in this study. In the laboratory, these subjects performed back-stepping to the backhand side with a concurrent overhead stroke, a single-leg landing on the force plate, and a return to the starting position. The kinematic data in the stance phase were normalized ranging from 0% as initial contact to 100% as toe-off; and 0% as initial contact to 100% as maximum knee flexion in the impact phase. Results The knee valgus angle in female players was significantly higher in initial contact (5.06 degrees +/- 6.83 degrees vs - 5.10 degrees +/- 4.30, p = .001) and maximal knee valgus angle (7.58 degrees +/- 9.54 degrees vs - 3.93 degrees +/- 4.22 degrees, p = .004) compared to male players. The knee valgus moment was significantly higher in male players than female players ( - 0.09 +/- 0.12 vs 0.03 +/- 0.10 N center dot m/kg, p = .032) in initial contact during the impact phase. During landings, female badminton players had lower hip flexion angles, greater knee valgus angles, and greater ankle dorsiflexion angles. Conclusion Female badminton players presented higher knee valgus angles but smaller knee valgus moments compared with male players during backward single-leg landings. The concomitant kinematic and kinetic changes of the hip, knee, and ankle joints also can play an important role in the higher incidence of ACL injury in female athletes.