As he watched male and female graduate students in his lab run, stop and then cut to the side, biomechanical engineering professor Tom Andriacchi saw distinct differences in how their knees responded. Reviewing films of women’s basketball games confirmed what he suspected: almost all the women landed with their body mass slightly off-center, which can cause their knees “to buckle, like a column.”
Andriacchi’s observations help explain a phenomenon noticed by many coaches, trainers and team doctors: as women’s participation in athletics has increased and intensified, they’ve become more likely than their male counterparts to suffer disabling injuries to the knee’s anterior cruciate ligament, or ACL. Seventy percent of women’s ACL tears result from noncontact play.
“There’s no question that more women are playing sports at a higher level and playing year-round,” says Elaine Lambert, team physician for several women’s varsity sports at Stanford. Women are stronger than they used to be, she adds, and “as their muscles get bigger, they’re putting ligaments and tendons at more force.”
ACL injuries can decimate a squad, as they did the women’s basketball team in 1998. In the last game of the regular season, starting forward Vanessa Nygaard, ’97, suffered the second ACL tear of her college career. Four days later, leading scorer and rebounder Kristin Folkl, ’98, came down hard from a practice shot and tore her knee. In the first round of the NCAA tournament, the team lost to Harvard, 71-67—the only time ever in college basketball a No. 1 seed has lost to a No. 16. The injury also is excruciating. Women’s basketball coach Tara VanDerveer claims to know an ACL tear when she hears the invariably accompanying scream.
There are several theories about what causes ACL tears and how to prevent them. “I think it’s a matter of overuse,” says women’s soccer coach Andy Nelson, who used to play 40 games a year in his native England. He compares that with the 100 tournaments many high school students play each year in the United States, hoping to catch the eye of college recruiters, and deems the American practice “ridiculous.”
Many experts say that an imbalance between women’s quadriceps and hamstrings puts excessive strain on the ACL, and a narrow notch in the female knee can “act like a guillotine to cut through the ACL,” as Nelson puts it. Some specialists think hormonal changes also may adversely affect tissue.
Andriacchi’s work may help remedy the problem. He hopes to head to the Stanford soccer fields this fall, to verify his lab observations and see how varsity knees perform. “What we find could lead to new training methods,” he says.
