Unless you've been living under a rock, you've probably noticed how torn ACLs have become much more prevalent these past few years. In fact, this type of knee injury has become so common that nowadays it's almost synonymous with a broken leg or a bad case of the flu....that sidelines you for the rest of the year.
Let's make no mistake, a torn ACL is a very serious injury to the knee joint. In fact, the rise of ACL tears has been almost historic, particularly in the NFL this year, with 41 individuals already tearing their ACL compared with only 25 in 2011.
So, what gives? Well in the case of the NFL, there are new rules that have directed contact away from the head, and towards the lower body, creating a lot more injuries. These are the unpreventable kind (like when Rob Gronkowsi's knee was blown up all over Gillette Stadium). But, other, non-contact injuries like Derrick Rose sustained last year, are prime examples of injuries that most likely could have been avoided. Why? They were non-contact injuries, that came without anyone actually touching them.
Taking a step back, it's important to look at how an ACL gets torn. Specifically, it often occurs when a knee caves inward and is put under a ton of valgus stress (yes, it's as ugly as it sounds). Unable to bear the motion and subsequent force, the ACL can be torn. It's often been said that young females are the most susceptible to ACL injuries, since the angle of their hips can increase the valgus stress placed on their knees, especially when playing sports.
Furthermore, two months ago, doctors discovered a new knee ligament (yes, really) that often goes hand-in-hand with a torn ACL (click here if you want to get your nerd on). Safe to say, knee instability will rear its ugly head in one of these forms, especially if you're playing at top speeds.
Hooookay so....how do we prevent it? Or, in the case of young female athletes, is there anything we can do to prevent the risk? Fortunately, the answer is yes, but it's not a sexy answer: ACL prevention is just another phrase for getting stronger.
Not to sound like I'm banging my head against a wall (although sometimes I actually am), but the best exercises for preventing ACL injuries are - you guessed it - squats and deadlifts. When performed properly, these motions will strengthen the musculature and ligaments around the knee, while also establishing correct motor control of the hips, knees, and ankles (in fact, I'd argue that non-contact ACL tears are largely the result of a neuromuscular disconnect, but that's for another day!).
Further, it's important to think about training single leg movements, as taking away your other leg puts more of a stress on the planes of motion that you'll be exposed to in sports (almost every sport is played on one leg at a time.) Something like a rear-foot elevated split squat, single leg squats, or a single leg deadlift, is going to expose your joints to the forces in different planes of motion, plus challenge your balance and single leg strength!
Our society has become much more sedentary, and as a result, we're much weaker and move much more poorly than previous generations. So, what do you think will happen when you take weaker individuals and put them in a full-speed sport such as basketball, football, hockey, etc.? They get injured! In no way is that meant to say that Gronkowsi or Derrick Rose aren't strong....but in the era of having everyone be bigger, stronger and faster, bodies will break down if they still don't practice good movement patterns and the basics of strength.
As Mike Boyle has stated, ACL prevention is simply just good training. Move well, get strong, stay strong....and your chances of blowing out an ACL will be greatly reduced.