Now that we are all familiar with the susceptibility of ACL tears or ruptures in all forms of sport, let’s dive into one of the less understood duties of the ACL, rotational stress. As far as non-contact ACL injuries go we have looked at the common mechanisms such as hyper-extension of the knee or that knock-knee or valgus position. But what about when we go to cut on the field or court? Or a quick change in direction creating a large amount of force? The knee will rotate while the foot is fixed on the ground and the ACL is tasked to prevent excessive movement in that type of closed chain rotation (the femur rotating on the tibia while the foot is fixed to the ground). A quick change of direction or plant and cut maneuver can place our knee in a provocative position, especially if we have not gone through a thorough ACL prevention program. The pairing of excessive knee valgus with the foot planted (causing excessive rotation within the knee) places an astronomical amount of stress on the ACL.
So what can we add into our ACL prevention programs to optimize our sport specific movements while reducing rotations stress? Fox (2018) correlates a landing and cut pattern with reduced ACL stress with a forefoot land (on the ball of your foot) and trunk rotation and slight lateral flexion which optimizes base of support and allows for an explosive movement into the new direction. The trunk movement over the plant knee allows for improved force absorption through the entire body and ultimately allows us to exert a larger amount of force against the ground for a quick and explosive directional change (see photo).
ACL prevention programs are quickly becoming a popular standard for athletes, but the program needs to be fully inclusive. Glute, hamstring, quadricep, and hip strength is of extreme importance, but we need to ensure we are not leaving out the sport specific tasks like change of direction. Drills such as the T-Test or partnered change of direction exercises should be paramount in any program. ACL prevention programs are not only there to reduce the possibilities of ACL injuries in practices or competitions, but they are there to develop better athletes and performance.
- Fox, A. S. (2018). Change-of-direction biomechanics: is what’s best for anterior cruciate ligament injury prevention also best for performance?. Sports Medicine, 48(8), 1799-1807.
- Ferretti, A., Monaco, E., & Vadala, A. (2014). Rotatory instability of the knee after ACL tear and reconstruction.Journal of Orthopaedics and Traumatology, 15(2), 75-79.