Why is it Important?
It is estimated that of the nearly 750,000 sports injuries that occur in the US every year, between 100,000 and 200,000 of them will be ACL injuries. Of those, between 70-84% are classified as non-contact, which means they happen without colliding with another player or the ground. Females are 2.5-10 times more likely to get the injury than males.
Once your ACL is torn, the average medical bill for surgery is around $25,000. Recovery time is usually around six months, including long and at times painful rehabilitation sessions with a physical therapist. Even if the surgery goes well, it is unlikely that it will return to the same level of performance as you had from it previously, and one study showed that 12 years later 82% of patients exhibited radiographic changes and 51% had developed Osteoarthritis in the knee.
Players commonly suffer psychological damage too, losing confidence in tackles and other situations, which can take more therapy and training to overcome.
What Causes it to Happen?
Non-contact ACL tears tend to occur when players change direction and decelerate at the same time. This often takes the form of cutting inside and collapsing your outside knee in towards the other leg. It can also occur when landing from a jump in or near full extension, again, causing the knee(s) to collapse in.
There have been many different arguments about what body weakness allows the injury to occur to certain people – ranging from variations in anatomy to changing hormone levels. One more recent suggestion is that females are more quadricep-dominant whereas males are more hamstring dominant. Generally on landing a jump, males tend to fire hamstring muscles more than females. Muscular fatigue from overuse and growth could also be a factor, as well as biomechanical factors to do with your body position at various times. Long story short: no one is completely sure what raises the incidence of non-contact ACL injuries, particularly in females.
What is it?
We probably should have mentioned this earlier.. The Anterior Cruciate Ligament is one of the four major ligaments in the knee. It connects the tibia and the femur and is located directly between the two bones (the MCL and LCL are located outside of the joint itself). As the name suggests, it is located towards the front of the knee, ahead of the PCL (Posterior Cruciate Ligament).
Ligaments hold bones together, so the ACL does not move anything (like muscles and tendons do), it contributes to the stability of the knee. Without one your knee can feel loose, particularly when turning in certain directions.
What can be done about it?
Studies have show than through specific traning the incidence of non-contact ACL injuries can be reduced by up to 87%. This can be as simple as modifying your warm up routine before practice and games, having experts look at the form of your players to isolate those with collapsing knees, and working on strengthening certain muscle groups for those players.
We have created warm up and strengthening routines that you can use for your players here.
We want to thank Justin Dudley for helping us write this article. Read our interview with him here.