New Studies on ACL Tears

Team physicians take a closer look at the role of hormones in ACL tears.

By Staff

Athletic Management, 13.6, October/November 2001,

This summer, two new studies were released linking ACL injuries in female athletes to their estrogen levels. Although the exact time when athletes are thought to be more prone to injury varied, the studies fuel a long-standing debate on how large a factor hormones play--and what to do about it.

For the past decade, team physicians have been analyzing reasons why female athletes are much more susceptible to ACL injuries, especially in the sports of basketball and soccer. Three theories have emerged: anatomical differences, neuromuscular differences, and hormonal fluctuation differences.

One study, headed by Dr. Edward Wojtys, Medical Director of the University of Michigan's MedSports Program, found that women have a significantly greater chance of ACL injury during the ovulatory phase of their menstrual cycle (days 10 to 14, when estrogen levels peak) than during other times of their cycle. The study also found that women not taking oral contraceptives had a greater number of ACL injuries than those on birth control pills.

The second study, led by Dr. James Slauterbeck, Vice Chairman of Orthopedics at Texas Tech Medical Center and a team physician for Texas Tech, looked at injuries during two phases, the follicular (first half) and luteal (second half) phases of a woman's menstrual cycle. He found most injuries occurred during the final days of the luteal phase and the first days of the follicular phase, around the time of menses.

The studies completed this summer used much more reliable reporting methods than those used in past studies, and thus have garnered the attention of team physicians and athletic trainers. Wojtys' study was presented at the American Orthopaedic Society for Sports Medicine's annual meeting and garnered the O'Donoghue Sports Injury Research Award.

However, experts emphasize that such studies are only a first step toward developing any possible new strategies for preventing the injury. There are more questions than answers at this point, and female athletes should be reassured that proper training is still their best bet for prevention.

"Based on the knowledge that we have, it would be a mistake to say that female athletes are more or less susceptible to injury at particular points in their cycle, or that just because their ligaments are more lax here they are more at-risk or less at-risk of injury,"says Dr. Sandra Shultz, Assistant Professor and Interim Coordinator of Graduate Programs in Athletic Training and Sports Medicine at the University of Virginia. "So, I don't think we can make any recommendations to athletes based on their menstrual cycle, or hormones, or birth control pills related to ACL injury."

Athletic trainers, researchers, and team physicians agree that the main thing to focus on at this point are those things that we do know something about and that have been shown to benefit athletes. "I think what you have to focus on are factors or possible factors that we can make a change in,"says Shultz. "Part of that is through preventative training. Studies show that doing some kind of preventative training program that works on landing, on cutting with good technique, and on hamstring strength does appear to lead to a reduction in injury rate."

Dr. Carol Otis, Primary Care Physician in Women's Sportsmedicine at Kerlan-Jobe Clinic, in Los Angeles, a former team physician for UCLA, and current team physician for the Sanex women's professional tennis tour agrees. "There are differences in landing and in hamstring and quad activation,"she explains. "So, the most important thing athletes can do is to work on their technique, particularly landing and taking off. They also need to make sure they have the proper footwear for the surfaces they're going to be playing on."

A more comprehensive article on this topic is running in the November issue of our sister publication, Training & Conditioning. This and other articles on preventing ACL injuries can be found on our Web site,, by typing "ACL"into the search field.