Female athletes may be 2.4 to 9.7 times more likely to sustain an anterior cruciate ligament (ACL) injury than males (Arendt et al., 1995; Gwinn et al., 2000). The majority of ACL injuries (78%) are from non-contact injuries such as planting, cutting, or landing from a jump (Noyes et al.,1983). In a retrospective survey on female basketball players, 58% reported landing from a jump when the injury occurred (Gray et al., 1985). The ACL is most susceptible to injury when the body is in forward flexion, hip adduction, internal rotation, 20-30° of knee flexion, external rotation of the tibia, and foot pronation (Ireland et al., 1997). Females are more likely than males to land with these risky characteristics, especially increased knee valgus (Chappell et al., 2002; Ford et al., 2003) and decreased knee flexion (Chappell et al., 2002). A combination of biomechanical, neuromuscular, hormonal, and anatomical differences may contribute to gender differences in ACL injury and landing mechanics. Jump-training programs that include stretching, plyometrics, and weight lifting have been shown to not only decrease varus and valgus moments at the knee, but also decrease the rate of non-contact ACL injuries (Hewett et al., 1996; Hewett et al., 1999). Research studies have yet to evaluate athletes of different age groups. Identifying when these landing differences occur during age may indicate when training programs should be implemented to have the greatest impact on decreasing the risk of ACL injury. All three age groups tended to demonstrate landing mechanics that may place them at risk for injury: knee valgus on contact with a more erect position. These results suggest that implementation of jump-training programs may benefit female athletes as young as 6th grade if the goal is specifically to alter these kinematic factors. Younger participants may be already demonstrating mechanics that may be a risk factor for ACL injury.
© Copyright 2004 Annual Meeting of the American Society of Biomechanics. (Presented on poster September 9-10, 2004 at the ASB meeting in Portland). Alle Rechte vorbehalten.