Are Knee Injuries Tied to Menstrual Cycle?

FRIDAY, Oct. 19 (HealthDay News) -- Menstrual cycle-related changes in nerves that control muscle activity could explain why female athletes are more likely than males to suffer knee injuries, especially anterior cruciate ligament (ACL) tears and chronic pain, according to a new study.

The findings may lead to new ways to prevent knee problems in female athletes, according to the researchers.

The researchers measured the activity of nerve fibers and the muscles they control around the knees of female volunteers over the course of their menstrual cycles. The firing rates of these nerves were much higher in the week before a woman's next period than earlier in the menstrual cycle.

This difference in firing rates could affect the stability of the knee joint and possibly make it more susceptible to injury, the researchers explained.

"Our results suggest that muscle activation patterns are altered by the menstrual cycle," Matthew Tenan, of the University of Texas, said in an American Physiological Society news release. "These alterations could lead to changes in rates of injury."

The findings were recently presented at the society's meeting on integrative biology of exercise in Westminster, Colo.

Previous research has focused on male/female differences in muscle structure around the knee as the main reason for the increased risk of knee injuries in female athletes. These findings suggest that menstrual-cycle-related hormone changes may also play a role, Tenan and his colleagues said.

Data and conclusions presented at meetings typically are considered preliminary until published in a peer-reviewed medical journal.

More information

The American Academy of Orthopaedic Surgeons has more about knee injuries.

SOURCE: American Physiological Society, news release, Oct. 10, 2012