The anterior cruciate ligament (ACL) is an extremely important ligament in terms of knee stability.  Tears of this ligament are commonly seen in high school and college aged athletes, with females being more prone to this injury. In most cases, injuries to the ACL are non-contact in nature, which means there was no player-to-player contact. There are several common biomechanical characteristics that are associated with non-contact ACL injuries, which we will explore in this article.

Research has commonly pointed towards four motor behavior patterns that are associated with ACL injury.

1. Inward collapse of the knee or dynamic valgus (ligament dominance) places extra stress on the passive structures of the knee and is associated with poor control of the hip joint and, less so, the foot.

2. Limited knee flexion (quadriceps dominance) is commonly seen in individuals who have suffered ACL injuries. A strong contraction by the quadriceps translates to a stiffer landing and increased anterior shear stress on the ACL.

3. Asymmetrical weight bearing (leg dominance) is seen in activities that are normally characterized by equal loading of each leg. When this happens, the loaded leg is put under greater stress, including the ACL.

4. Lateral trunk flexion (trunk dominance) relates to an individual’s inability to precisely control their trunk in three-dimensional space through coordinated trunk muscle action. Several studies have demonstrated that trunk proprioception and control serve as predictors of future risk of knee ligament injury.

If you have suffered an ACL injury or are hoping to reducing the risk of suffering one, implementing a neuromuscular training program is an extremely important step. The following link will take you to a program that has been well studied and shown to reduce rates of ACL tears when implemented.

https://aclstudygroup.com/pdf/pep-program.pdf

References:

1. Hewett TE, et al. Understanding and preventing acl injuries: current biomechanical and epidemiologic considerations. N Am J Sports Phys Ther. 2010.

2. Mandelbaum BR, et al. Effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. Am J Sports Med. 2005.