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NEW YORK (Reuters Health) - Female athletes are at greater risk of a potentially serious knee ligament injury than their male counterparts -- but a fairly simple training regimen might help reduce those odds, a small study suggests.
The injury in question affects the knee's anterior cruciate ligament, or ACL. ACL tears are common in certain sports and are a particular threat to female athletes -- who have four to six times the risk of their male counterparts in the same sport.
In the new study, Korean researchers found that among 22 high school basketball players they followed, girls who followed the training regimen for eight weeks showed changes in jumping ability that could lower their odds of tearing the ACL.
The researchers, led by Dr. Bee-Oh Lim of Seoul National University, report the findings in the American Journal of Sports Medicine.
The ACL is a tough band of tissue that runs from the thigh bone to shin bone and plays an important part in stabilizing the knee joint. When it tears, it's often the result of a sudden, forceful twist -- such as an awkward landing from a jump that torques the knee.
Athletes in sports that require quick pivots and jumps -- including basketball, soccer and volleyball -- have the highest rates of ACL injury.
Experts are not certain why female athletes are more vulnerable, but the general consensus is that differences in biomechanics may play a role.
Compared with males, for instance, female athletes tend to have a greater imbalance in the quadricep and hamstring muscles at the front and back of the thigh, respectively. Females typically have more strength in the quadriceps and greater flexibility in the hamstrings.
Research also suggests that females tend to bend their knees less deeply and have a less stable joint alignment when landing from jumps.
For the current study, Lim's team tested a training program designed to address these differences.
The researchers randomly assigned 22 female high school basketball players to one of two groups: one that added the training to their regular team practice and one that did not.
Girls in the former group spent the first 20 minutes of their practice time performing exercises designed to improve their jumping ability and strengthen and stretch the various muscles of the legs and hips.
After eight weeks, the researchers found, girls in the training group were showing better form on a standard jumping test. They also had a more balanced activation of their quadriceps and hamstrings while jumping -- measured via electrodes placed on the muscles.
The researchers did not study whether all of this translates into a lower rate of ACL tears. However, other studies have shown that similar training regimens may cut the risk.
Still unclear is how long athletes have to train to lower their risk of ACL injury, Lim's team notes. Girls in this study trained for eight weeks, but some research suggests that six weeks may be enough.
SOURCE: American Journal of Sports Medicine, September 2009.
