NEW YORK, June 15 (Reuters) While female athletes are usually more likely than men to tear the knee's anterior cruciate ligament (ACL), the sport of lacrosse appears to be an exception, according to a new study.
Since 1989, researchers found, U.S. women on college basketball and soccer teams have suffered ACL injuries at three to four times the rate of their male counterparts. When it comes to lacrosse, however, men and women have shown nearly identical rates of the injury.
The gender gap observed in other sports disappeared because female lacrosse players had a relatively low rate of ACL injury, while male players had an unusually high risk, the study authors report in the American Journal of Sports Medicine.
The reasons are uncertain, but the researchers suspect that the level of physical contact in a sport is key to the risk of ACL injury. While men's lacrosse involves more contact than either soccer or basketball, the women's game is non-contact.
Contact in lacrosse may cause an ACL tear indirectly, explained study co-author Dr. Anthony Beutler of the Malcolm Grow Medical Center at Andrews Air Force Base in Maryland.
For instance, colliding with another player, or being distracted by the threat of a looming lacrosse stick, could cause an athlete to awkwardly pivot or land from a jump, which in turn can rupture the ACL.
The ACL is a tough, fibrous band that runs from the thighbone to the shinbone, serving as a major stabilizer of the knee joint. When it tears, it's often due to a hard twisting motion. So ACL injuries are particularly common in sports that require lots of pivoting, jumping and sudden stops and starts, such as basketball, soccer, volleyball and lacrosse.
Studies have long shown that women are up to eight times more likely to suffer a sports-related ACL tear than men are, and researchers have offered a number of possible explanations -- including differences in strength, training and anatomy between male and female athletes.
The findings on lacrosse are ''fascinating,'' Beutler told Reuters Health, because they show that the sport's characteristics, and not just the player's, are important in ACL injury.
The results are based on injury data collected by the National Collegiate Athletic Association between 1989 and 2004. The rate of ACL injuries was stable across the 15 years, and consistently higher among female soccer and basketball players than among males.
However, female lacrosse players had only about half the risk of female soccer players, while the opposite pattern emerged for men.
Male lacrosse players were 50 percent more likely than soccer players, and twice as likely as basketball players, to suffer an ACL tear.
Changing men's lacrosse rules to make it more like the women's game could conceivably lower the ACL risk, Beutler said, but that probably wouldn't be a popular move.
He noted that a large trial is currently investigating ways to prevent ACL tears in athletes, and researchers should know much more about what works and what doesn't in the coming years.
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