On Bended Knee

Gri

zzled old jocks sitting around the training room comparing war stories and showing off battle scars are as familiar in organized sports as jockstraps and body odor. Today, however, with female sports participation at an all-time high (2.5 million high school girls and 145,000 college women will compete this year), the athletes telling war stories are more likely to have smooth faces and wear sports bras. The injuries have also changed. One in particular has sports doctors worried.

It's a knee injury--damage to the anterior cruciate ligament, or ACL. As increasing numbers of young women lace up their cleats and head out onto the field, more are showing up in infirmaries and operating rooms with a partly torn or completely ruptured ACL. This is a lot more serious than an ankle sprain or a jammed finger. The ACL is the knee's most important stabilizer and if severely injured can require surgical repair and cause permanent, perhaps career-ending damage.

Several studies have shown that women are considerably more vulnerable than men to ACL injury. By some estimates, they suffer this injury two to eight times as frequently as men. For years, doctors thought this had something to do with weakness in the joints and ligaments. The evidence, however, doesn't support the notion. What research has shown is that there are inherent anatomical differences between male and female athletes--differences in pelvic width and alignment of the leg bones--that make women more likely to injure their ACL. Unfortunately, these anatomical features can't be modified.

But if you are a female athlete, you don't have to take knee problems as a given. There are several things you can do to reduce your risk of ACL injury. One is strength training. The muscles around the knee--in particular the quadriceps (front leg muscles) and hamstrings (back leg muscles)--play a critical role in keeping the knee stable during athletic performance. Strength in the hamstrings has been shown to protect the ACL from excessive strain; women, however, tend to be stronger in the quadriceps, creating an injury-prone imbalance.

Research has also shown that women jump and land differently than men do. This is critical because a high percentage of ACL injuries occur during these moves. Women are less flexible in the hip and knee joints and tend to land in a position of extension rather than the preferable flexed position. Special jump training involving wall jumps and single-leg hops strengthens leg muscles and can create more favorable body mechanics.

Finally, women can protect their knees by improving their balance. This can be done by building up the muscles surrounding the knees. These muscles serve as shock absorbers, reducing the force that eventually gets transferred to the ACL and protecting against excessive rotation at the knee joint. Working on balance boards for as little as 20 minutes a day over a period of six weeks can improve coordination of the hamstrings and the gastrocnemius muscles in the calves, protecting the ACL during athletic twists and turns. Training properly and developing physical conditioning will not only help level the playing field for female athletes but also keep them on it longer.

Dr. Ian is a medical correspondent for nbc's Today show. E-mail: ianmedical@aol.com. For more on knees, try orthoinfo.aaos.org