Unintended Side Effect of Women's Rise in Sports Participation: Serious Knee Injuries

Jan. 14, 2000 (New York) -- As women go full tilt into competitive sports, they are also suffering unnecessary knee injuries, particularly when they fail to train weak muscles, reveals a study in the Nov/Dec issue of American Journal of Sports Medicine. Researchers tell WebMD that women can prevent most serious knee injuries if they take training seriously, setting their sights on strengthening muscle, improving balance, and proper landing during sports activities.

Frank R. Noyes, MD, senior author of the study, says that women suffer injuries to their anterior cruciate ligament (ACL) on the order of "4-6 times more [often] than men." In previous research, Noyes, Timothy E. Hewett, PhD, and others demonstrated deficits in women's lower leg muscles, particularly the hamstrings and calf muscles, that place women at increased risk for landing hard and injuring their knees in sports.

"There are lots of theories as to why this is so," Noyes tells WebMD. One theory is that women have inherently weaker muscles and that they favor their stronger quadriceps, which puts increased pressure on the knee when pivoting or landing in sports. Estrogen is also believed to make women's ligaments smaller than men's. Women also have a wider pelvis, which changes the angle of their knee joint and may contribute to increased injuries in 'jumping' sports.

Noyes and Hewett found that women participating in high school soccer, basketball, or volleyball who did not train were far more likely to hurt their knees than women who trained. In their study of 1,263 female and male athletes, they compared knee injury rates in women who participated in a six- to eight-week neuromuscular conditioning program prior to the sports season with another group of women who did not train, and a group of untrained male athletes.

Interestingly, the study demonstrated a similar knee injury rate for women who trained as for men who did not, a finding that has piqued the interest of the researchers. They report a total of 14 serious knee injuries, including 10 in the untrained female athlete group, two injuries among the trained women's athlete group, and two in the group of men who did not train.

"We now have developed a very good conditioning program to overcome muscle and coordination problems," says Noyes, who is president and CEO of Cincinnati Sportsmedicine and Orthopaedic Center in Cincinnati, Ohio. The program that they developed emphasizes leg curls, building the calf muscles, balance training, and beginning the program long before the sports season starts.

Much of the program emphasizes retraining women in deep knee flexion so that women can land and pivot safely in sports, according to Hewett, the study's lead investigator, who is director of applied research at Cincinnati Sportsmedicine and Orthopaedic Center.