"A torn ACL is the No. 1 reason women miss time from sports because of injury. And women are three to six times more likely to tear an ACL than men," according to the Mayo Clinic. Dr. Timothy Hewett, head of sports medicine at Mayo, states, "the reason women tear their ACL more often than men is because they tend to rely on different muscles and ligaments than men while jumping and running." Looking a little deeper, we also find that women have a slight anatomical disadvantage around the knee joint. With a greater Q angle -- the angle between the anterior superior iliac crest (ASIS) and the patella tendon, or the hip to the knee -- the knee can become less stable under stress and inwardly collapse more easily, resulting in more ACL tears.
How do we help mitigate and combat this unfortunate happening, at least from a weight-training perspective? We focus on strengthening key areas in the lower extremity. How do we do so? Two words: Squat. Deadlift.
Why the squat: According to an article titled ACL Injury Prevention Tips and Exercises: Stay Off the Sidelines!, by the Hospital of Special Surgery, "Having adequate strength in your hips and thighs is key to providing support for your knees and preventing ACL injuries." A properly executed squat significantly develops the hips and thighs, as well as the glutes, abductors, and hamstrings. (A stronger gluteus medius and gluteus maximus can directly fights against knee valgus.) As a result, we improve the musculature and strength of our lower extremity, which helps support and protect the knees; this allows our body to withstand increased forces placed upon it. In addition, the squat is an invaluable tool used to enhance balance; it requires the body to maximize motor control and learn how to maintain strict positioning while under load. When musculature, strength, and balance improve, we're able to run, jump, and move with less likelihood of injury.
Why the deadlift: According to Designing Resistance Training (4th ed.) by Steven Fleck and William Kraemer, "when the quadriceps strength is greater than the strength of the hamstrings, both the hamstrings and the anterior cruciate ligament (ACL) become more susceptible to injury because they are responsible for preventing anterior translation of the tibia on the femur. If the quadriceps can produce more anterior translation than the hamstrings and ACL can tolerate, injury is likely. Therefore, increasing the strength of the hamstrings in relation to the quadriceps could theoretically reduce the risk of ACL injury in women." Unfortunately, it is far too common to have a quadriceps-hamstring imbalance. Due to everyday activities and sport, we begin to rely on and develop our quadriceps at a disproportional rate. This is one reason to incorporate the deadlift into training. Like the squat, it activates a number of large lower-body muscles; however, this particular exercise focuses more on the posterior chain -- the hamstrings, glutes, and erectors, in particular. With the posterior focus, we can attack any imbalance while still benefiting other key areas.
ACL tears are never 100% preventable, but, from a weight-training standpoint, we can do our part to help lower the risk of injury. This holds true not just for women, but also men. We simply highlight the female population due to the drastic statistic skewed against this segment of the population.