ACL tears happen suddenly, almost without fail, every high school sports season. A teenager jumps or pivots fast to get the ball. The teen may feel a pop in the knee, but usually can walk off the field. Within 24 to 48 hours the teen’s knee is severely swollen.
If your teenage athlete is a girl, her risk of tearing the anterior cruciate ligament (ACL) is four to six times greater than a boy’s. Why? At first, researchers thought hormones and girls’ body structure increased their risk. But studies now indicate those are minor points.
More likely, girls are at greater risk for ACL tears because of two factors, both preventable:
- Biomechanics. Girls tend to hold their bodies more upright than boys when they jump, cut and pivot. They also tend to let their knees turn inward into a knock-knee position.
- Muscle imbalance in the thighs. Girls’ hamstrings – the muscle in back of the thigh – are generally weaker than their quadriceps, the main muscle in front of the thigh. Girls’ quadriceps can overpower their hamstrings, which puts pressure on the knee.
Research shows that prevention programs can reduce risk of ACL tears in girls by over 80 percent. Unfortunately, many coaches aren’t aware of prevention programs and don’t incorporate them into training programs.
Girls who strengthen their hamstrings and learn how put their knee directly over their foot can protect themselves. Here’s how:
- View Vanderbilt University’s highly regarded ACL Prevention Program. The video or slides show girls doing specific agility drills, stretches and exercises to help prevent ACL tears. Follow the program three times a week.
- If your teen has difficulty doing the workout on her own, find a physical therapist to work with her.
Unlike other ligaments, a torn ACL cannot heal itself. Young athletes who want to stay active throughout their life usually require surgery to repair a torn ACL.
The surgery is very successful in stabilizing the knee and restoring function, but if you’ve torn your ACL once, you have a higher risk of premature arthritis and tearing the ACL again in the same knee or the opposite knee. Prevention is a far better solution.
Reviewed by: Elizabeth W. Lee, M.D.
Last reviewed: June 2019