Jennifer Lovejoy, Arivale Chief Science Officer, PhD
Your anterior cruciate ligament (ACL) is one of the many ligaments connecting the upper and lower portions of the leg at the knee. For most people, it’s the one thing you really don’t want to injure. Whether you, a close friend, or the star of your fantasy football line up have experienced an ACL injury, you know full well an ACL tear often requires surgery and a lengthy recovery period.
Many things influence your likelihood of an ACL injury (hormones, nutrition, footwear, core strength, flexibility, and bad luck to name a few). While there currently isn’t much scientific consensus around genetics that increase your predisposition for ACL injury, there is a genetic variant that could help protect you from a tear.
Genetics, Collagen, and ACL Injuries
Tendons and ligaments are composed primarily of collagens—a structural protein that’s more commonly known for keeping your skin, hair, and bones healthy.
Type 1 collagen is the most predominant collagen in tendons and ligaments, and the COL1A1 gene helps make its proteins. In one particular COL1A1 variant (rs1800012 for the curious), the presence of the A allele can alter the normal structure of type 1 collagen. While scientists are unclear on exactly how this collagen change affects ligaments, studies do show that individuals with two copies of the A allele could have a decreased risk for ACL injury.
One study, in particular, looked at people with ACL injuries and people who had never injured their ACL. The uninjured control group had ten times the amount of people with the AA genotype in the COL1A1 variant. Researchers hypothesized that the AA genotype’s change to type 1 collagen structure could help protect against ACL injury.
It’s fairly uncommon to have the AA genotype (only 2.5 percent of Arivale members do). And interestingly enough, this same structural change to collagen caused by this variant may in reverse create an increased risk of bone fractures. Give a little, take a little, or so they say.
Preventing ACL Injury
Let’s be clear about one thing. Even if your genetic predisposition for ACL injury is lower, you’re still no superman. There are many other factors that go into injuries, some of them in your control and some of them not. Regardless of your genetic makeup, taking care of your body, especially when participating in high-intensity activities, is always a good idea.
Here are some tips from our coaches on preventing exercise-related injuries.