Epidemic of knee injuries afflicts female athletes

June 5, 2001
The Ottawa Citizen

Answer may lie in teaching women to jump

"I pretty much just fell to the ground." The injury Laura suffered is not uncommon, something she soon found out. "I never realized how often it happened until I did it and talked to people about it," said the South Nepean Iron Eagles player, now 18.

The painful pop and tear of the anterior cruciate ligament, or ACL, is happening to more and more females who play bone-jarring, stop-and-start sports. Soccer, basketball and volleyball top the list of risky sports, and downhill skiing and gymnastics can can prove equally risky. Studies show females are two to eight times as likely as males to tear the ligament, but there's no definitive reason why. "It's a hot topic right now," said Dr. Don Johnson, director of the Sports Medicine Clinic at Carleton University.

Doing It Wrong, Doing It Right: Instructional video shows the way women tend to land after jumping, in a dangerous knock-kneed position.

"I just think, when you look at the size of the ligament, the knee wasn't meant to pivot the way we do."

The ligament is a five-centimetre band of ropy, white connective tissue that extends from the back of the thigh bone (the femur) to the front of the shin bone (the tibia). It prevents hyperextension and excessive rotation of the knee joint. An increasing number of women and girls are suffering knee ligament injuries as female sports leagues have grown in popularity.

Between 1996 and 2000 in Canada, female registration in minor league soccer increased 61 per cent -- from 167,913 in 1996 to 270,145 last year. The number of anterior cruciate ligament surgeries has also increased, with waits as long as a year in Ottawa. "I was the only one (in Ottawa) doing them 10 years ago," Dr. Johnson said. "Now there are two others doing it."

Doing It Wrong, Doing It Right: Female athletes are being taught to land, with side-to-side motion minimized.

He estimates there were 500 to 600 ligament surgeries in the region last year; one-third of those were on females (although females tear the ligament at a higher rate, more males than females play sports, which skews the surgery statistics).

While most male ligament tears are the result of a collision -- such as the one on Senators hockey player Mike Fisher, who was hit by a Bruins defenceman -- the majority of female ligament injuries are caused by landing a jump or making a pivot.

"Women's basketball in the U.S. has just been decimated," said Dr. Johnson, citing the recent ligament tears of several college stars, as well as Sheryl Swoopes of the Women's National Basketball Association, the women's professional league.

Theories abound on why women's ligaments are so much more prone to tearing than men's. High estrogen levels in the mid-point of the menstrual cycle may soften and stretch ligaments slightly, but whether this makes them more vulnerable is disputed. Lack of fitness doesn't seem to be a factor.

A four-year study of women at West Point military academy showed their ligament injuries were equally spread out over four years. "If it was just a conditioning thing, they would do it in their first year," Dr. Johnson said. Anatomically, the wider female pelvis can make women knock-kneed when they jump and land, straining the ligament. Men tend to land in a straighter position and have more hamstring strength, which bolsters the ligament. And while males bend their knees like hinges, females often pivot theirs like a ball-and-socket joint.

The answer may lie in teaching females to jump -- not higher, faster, stronger -- but straighter. In a 1998 U.S. study of 1,200 indoor-soccer players, 400 girls who spent six weeks working on jumping without caving in at the knees and other stability and balance exercises saw their injury rate drop to that of untrained boys.

"The untrained girls were five to six times more likely to blow out their knees," said Dr. Tim Hewett, University of Cincinnati sports medicine professor. "We think we're at the point now where we can make a difference."

Based on these findings, Dr. Hewett developed a jump-training video to help coaches and parents teach girls to control their side-to-side knee motion when they jump and land, and help them develop balance and hamstring strength. (It costs $39 U.S. and is available at www.sportsmetrics.net.) Word is spreading slowly.

A few hundred schools and colleges in the U.S. now use similar programs, as do the Chicago Bulls and Toronto Raptors basketball teams because the drills are also useful for males, Dr. Hewett said. "(But) we still have a long way to go. A lot of parents, coaches and athletic directors still don't know that this problem exists."

Dr. Johnson estimates that each ligament repair costs the Canadian health-care system $8,000. He'd like to see young girls start jump-training before even starting sports, especially given the year-long waiting list in Ottawa for ligament surgery.

"Ottawa's particularly bad," he says, because people come from as far away as North Bay for surgery. "You don't want to tell a kid who's 12 or 15 they have to stop sports for a year."

Laura Marier, the soccer goalie who hurt herself last year, had surgery and has regained the muscle mass in her leg after a year of rehabilitation. Wearing a brace, she recently played again for the first time since the injury.

"I think I got back quickly," she said. "It's kind of mental, too. "I don't regret playing soccer. I think there's risk in anything you do."