If you are a young female athlete, parent or coach of an athlete, you may be aware that adolescent girls have a 4 to 8 time higher risk of sustaining a non-contact anterior cruciate ligament (ACL) injury than male athletes participating in the same sports. While reasons for this may vary, an article published in Contemporary Pediatrics suggests that this higher risk factor is related to a female athlete’s neuromuscular control of knee motion during athletic activities such as landing from a jump or quickly changing direction:

Current evidence suggests that the primary reason girls are at greater risk than boys for noncontact ACL injuries is that girls tend to have less neuromuscular control of knee motion during athletic maneuvers. In other words, girls tend to use their muscles differently than boys when landing from a jump or quickly changing direction. Biomechanical studies have identified 4 neuromuscular strategies that are more common in girls and that may lead to dynamic knee valgus, a position that places the ACL at a high risk of tearing.

(1) Girls tend to use their quadriceps muscles much more than their hamstrings. Kinetic and kinematic analyses have found that during a jump landing or quick change in direction, girls have reduced knee flexion, increased quadriceps activity, and decreased hamstring activity compared with boys. This “quadriceps dominant” strategy has been shown to increase both anterior tibial translation and strain on the ACL.30 Notably, ACL strain is significantly reduced when there is co-contraction of the hamstrings.4

(2) Girls tend to have 1 leg stronger than the other, whereas boys tend to have equal strength in both legs. Asymmetry in leg strength promotes asymmetric weight distribution between the feet upon landing, causing a shift of the […]