Women’s Weakness in the Knees

Most often, they are season-ending injuries for professional athletes. Washington Redskins defensive back DeAngelo Hall is believed to have torn his ACL during Sunday’s win over the New York Giants, although an MRI had to be done to confirm the injury.

Duke defensive back DeVon Edwards, a college standout, is also benched for the season after tearing his ACL on Saturday during a game against Notre Dame. The Oregon Ducks and the San Diego Chargers both lost players last week — same thing.

More than 200,000 people in the U.S. suffer ACL injuries each year, most often while playing sports.

We typically hear about these injuries in regard to men, especially during football season. But women — whatever level athlete they may be — are far more likely than men to tear an ACL. Scientists at Johns Hopkins now say women are up to 10 times more likely to suffer this excruciatingly painful knee injury than male counterparts. Why?

Testosterone.

Previous studies showed an increased risk for girls and women of tearing an ACL due to differences in anatomy, strength, reflex times, and hormones. But this is the first time researchers found normal male rats with natural supplies of testosterone had stronger anterior cruciate ligaments, or ACLs, than those that had been castrated and no longer produced the hormone. Their findings were released last week in the journal The Knee.

“Testosterone may contribute to the ACL’s ability to withstand tensile loads and may be one of multiple factors responsible for the disparate ACL injury rate between men and women,” said William Romani, a physical therapist and sports medicine researcher, in a statement.

Related: Watch Your Knees, Please

Senior study author Jennifer Elisseeff, a biomedical engineer at Johns Hopkins University, said the new finding could eventually lead to techniques that use circulating sex hormone levels. These levels could identify athletes at higher risk for ACL injury who may benefit from training strategies to strengthen the ligament.

[lz_bulleted_list title=”Symptoms of Torn ACL” source=”http://www.emedicinehealth.com”]When you tear your ACL, you may hear a pop. You will also notice your knee give way or become unstable, and feel pain. This will, almost always, be followed by marked knee swelling over the next few hours because the ACL bleeds briskly when torn.[/lz_bulleted_list]

The ACL is a flexible, stretchable tissue that tunnels through the knee, connecting the femur, or thigh bone, with the tibia, or shin bone. More than 200,000 people in the U.S. suffer ACL injuries each year, ranging from partial to full tears, and most often while playing sports.

Romani, a former faculty member at Johns Hopkins who is now with the AARP Foundation’s Experience Corps, found that estrogen, a predominantly female hormone, reduces ACL strength. But he also found that knee ligaments in both sexes contain receptors for testosterone.

“Our thought was that while estrogen may make the female ACL weaker and more prone to injury, the male hormone testosterone may act to strengthen the ACL and protect it from injury,” Romani said.

While more work is needed to explain exactly which pathways and molecules testosterone and estrogen act through to influence ligament strength, and whether the hormones have the same impact on other ligaments in the body, there are steps you can take to protect your knees.

[lz_ndn video=30862470]

Training drills that work on balance, agility, and power reduce the risk of ACL injuries. Teaching the muscles that surround the knee how to react when placed under stress may help protect the knee joint when a potential injury situation exists.