Preventing the ACL Injury Epidemic
In recent years, we have seen a steady increase in the number of ACL injuries, particularly in young female athletes. Why is this happening and how can we prevent it? There are a multitude of possible reason for it, but the good news is that it is preventable. Much of the cause is due to the increased participation in sports over the past 30 years, and particularly the increased participation in women’s sports. Women are naturally prone to suffering ACL injuries because of a series of anatomical factors working against them. The most obvious of these, is the natural angle of the knee to the hip, also known as the Q-angle. Combine that anatomical predisposition to injury with the increase in athletic participation and you have yourself a recipe for disaster. So how can this problem be averted? Simply put, you can prevent it with the right strength and conditioning program, and I’ll explain why.
Balance is something that most people feel they do well, until they actually test it and see how good, or more likely, bad they really are at it. The positive? Once it’s recognized as a problem, it can be addressed and improved upon quickly. This is important because a lot of the mechanisms that help maintain good balance also help to prevent ACL injuries. I mentioned earlier that the angle of the knee to the hip, or Q-angle, is different in men and women. In women there is a greater lateral distance from the knee to the outside of the hip, or in other words, the knee is closer to the center of the body. This is important because part of the mechanism of ACL injuries is an inward buckling of the knee, and the greater that buckling the more likely there is an injury.
When we test and train balance, we often see this inward buckling of the knee, but it really involves the entire chain starting with the arch of the foot, the ankle, the knee and the hip. Once the arch collapses, the ankle buckles inward, then the knee, and by the time we get to the top of the chain, the muscles of the hip have trouble compensating to bring us back to a stable position. By training our balance, we not only develop an awareness and control of what these joints are doing, but we also help to actually strengthen the arch of the foot and the posterior chain (calves, hamstrings, glutes) which all work together to maintain a more stable and safer position.
Another problem we can attribute to that problematic Q-angle is landing mechanics. This is easily identifiable in most young females when they jump and you see their knees move inward toward each other, often even knocking together. In many young girls you may even notice it at slower speeds with movements like squatting. This inward movement is called knee valgus, and it is a big part of the equation when an ACL injury occurs. This is not just an alignment issue though, it’s a movement pattern and strength issue. When done properly, simple movements like squatting can help to re-teach the proper pattern in slow motion, as well as strengthen the muscles that help to prevent this particular movement. Alongside the strength training, working on proper landing mechanics through various methods like hurdle and box jump training are a great way to learn how to land safely and effectively. These drills can even be progressed to single leg landings when appropriate control is demonstrated.
Besides just the angle of their hips, women have another factor working against them; quad dominance. Some people tend to predominately use their quadriceps to help add stability to their knee joint, and some have the tendency to use more of their hamstrings. When it comes to guarding against ACL injuries, the latter is a much better way to do so. Since this article to this point is all about how women have a higher predisposition to ACL injuries, take a guess at who tends to be more quad dominant. While there are exceptions to the rule, women tend to rely on their quadriceps while men tend to rely on their hamstrings.
The reason that the hamstrings are a better option for the body to protect the ACL is because the ACL and the hamstrings both act together to prevent the lower leg from moving forward. The quadriceps on the other hand, pulls on the lower leg from the front. The hamstring is also helpful because inserts into the lower leg toward the sides rather than the middle, providing more lateral stability to the knee. Unfortunately, the muscles of the posterior chain are often neglected in training programs, but training them offers tremendous benefits. Increasing posterior chain strength, and teaching an athlete how to use their posterior chain properly, both help to protect the knee from the positions and forces that cause ACL injuries. There is also a performance benefit to training the posterior chain as it’s also responsible for creating most of an athlete’s power. Could anyone possibly need any further reasoning to focus on training their posterior chain?
The final preventable factor that we see in ACL injuries is control. Control includes being able to control the movement patterns in our legs as described in the last few sections, but it also involves being able to control our body in space; particularly our trunk. Young teenagers go through a lot of growth changes, particularly in their height. Once they start hitting their growth spurts, they often move like giraffes on roller skates while their coordination plays catchup. This is because their body’s motor patterns need to learn to adjust to the size of their new residence. While both men and women go through these spurts, in men the spurt is accompanied by increased testosterone and muscle mass, which help to control the new body that they’re not used to just yet.
Control of the core is of particular importance because when an athlete is changing direction, if they end up with too much side bend it will contribute to excessive force on the knee and additional strain on the ACL. By increasing 360-degree core strength and learning how to stiffen the spine during dynamic movements like jumping and cutting, we can continue to reduce the risk of injury to the ACL. Improving core stability is actually one of the best ways to prevent most injuries, as well as increasing performance in just about any task.
So there you have it, the formula for preventing most ACL injuries. Balance, mechanics, assistance, and control. All of these concepts practiced regularly in a well-balanced training program will give you both the strength and confidence that you need to stay healthy and performing at your best!
Have you suffered an ACL injury or feel that you could use some training to help prevent it from ever happening to you? Contact the staff at Olympia Fitness and Performance about our programs specifically for ACL post-rehab training and sports injury prevention!
Steve Zarriello is the owner of Olympia Fitness and Performance, located in Cranston, RI. He has been training clients of all different ages, abilities and backgrounds to help them reach their specific goals for almost 15 years. His primary focus is on working with golfers to help improve their ability to play the game and keep them pain free.
Hewett, T., Ford, K., Hoogenboom, B., & Myer, G. (2010, December). Understanding and preventing ACL Injuries: Current biomechanical and epidemiologic considerations – update 2010. North American Journal of Sports Physical Therapy. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096145/