The unprecedented surge of soccer-playing girls has revealed an unexpected statistic: high school girls are as much as 68 percent more likely to suffer a concussion while playing soccer than high school boys. And, the trend isn't just seen on the pitch. In sports where boys and girls play by the same rules, like basketball, girls are more likely than boys to become concussed.
13-year-old Megan Tarr was only ten when she received her first concussion, the result of a car accident, not her dizzying schedule of soccer, lacrosse, and track. The lingering effects kept her at home for the rest of summer vacation. Her mom, Shannon Tarr, thought it was a fluke.
"We were never thinking about it happening again," Tarr said. "When we got through it, it took about four months, we were just so happy that she got cleared to go back to sports and activity and resume normal lifestyle we never thought about her getting another one. We just didn't."
But this winter, that's exactly what happened. This time Meghan was playing indoor soccer when she was slammed into the walls and cleated twice. Even though she had felt a concussion before, Meghan didn't recognize the symptoms. "I just started playing right again," Meghan said.
When the brain suffers a concussion, it sets off what's called a metabolic cascade. Steady oxygen levels can help stave off the worst of the damage, but exercise, of the physical or mental variety, robs the brain of oxygen and prolongs the time it takes to recover. But, Meghan didn't know she had a concussion. So, she kept playing. The next day, her mom was out of town when Meghan attended a speed agility class and an Olympic Development Program soccer session.
"The other moms were like, 'she's just not herself, she's off balance, she doesn't seem right,'" Tarr recalled. "And the headache just got intense. It got to be on a scale of one-to-ten, a ten."
Meghan missed almost two weeks of school, and when she went back she was under strict doctor's orders not to study or take tests. Those rules were courtesy of Dr. Bill Meehan, Meghan's doctor and the director of the Sports Concussion clinic at Boston Children's Hospital.
In May, Dr. Meehan spoke at the 9th Annual Sports-Related Conference on Concussion and Spine Injury. In his talk, he merely hinted at the statistics that show females suffer a higher rate of concussions than males because at his clinic at Children's Hospital Dr. Meehan sees an equal number of boys and girls.
That's because the rate of concussion, or the number of concussions per unit of participation time, is a different measure than overall concussion risk. Boys still receive more total concussions than girls because of the sports they play.
But, the research also suggests that girls experience more severe concussion symptoms and take longer to recover than boys.
"They may, there’s some debate about this," Meehan said. "Some have suspected that maybe girls are just more honest. Boys are trying to be tough and trying to be macho so they’re saying they’re fine before they are, whereas girls say, 'Oh, I don’t want to mess up my brain. I’m gonna tell you the truth, I’m not better yet.' So it’s not clear yet, but there’s some evidence to suggest it takes girls longer."
While science catches up to these questions, Dr. Meehan recommends that boys and girls do the exact same things to limit their risk of injury — and it doesn't have anything to do with better helmets, concussion headbands, or mouth guards.
"Girls inherently have weaker neck muscles, they have less muscle bulk and less muscle strength in their neck, and so by strengthening their neck muscles, they might be able to reduce their risk," Meehan said. "The only reason I say I don’t tell them differently is I also recommend that boys do neck strengthening exercise, and so I recommend it to both, but it may have a potential for greater benefit in female athletes."
There are far more questions than answers when it comes to concussions and female athletes. Dr. Mary Jo Kane, Director of the Tucker Center for Research on Girls and Women in Sports at the University of Minnesota, says that's just one of the lingering effects of gender bias, 40 years after the passage of Title IX.
"So it just has not occurred to people until very, very recently to say, 'Hey, girls get concussions, too. We should do some research in this area,'" Kane said. "We are just starting to touch these issues but we have a long, long way to go."
Dr. Kane and her colleague, Dr. Diane Weise-Bjornstal, walk a fine line between keeping female athletes and their parents informed, without reading too much into what is still very preliminary data.
"Gender is but one of many influential variables on concussion," Weise-Bjornstal said. "History of concussion is a risk factor. What part of the head do you get hit on, what are the g-forces? There's just so much research going on out there... The number of variables influences this are somewhat overwhelming and yet that doesn't mean we don't take a look."
So, while Dr. Weise-Bjornstal keeps her eyes on the research and Dr. Kane works to publicize the results, both women hope that their efforts do not become part of a greater conversation about whether women and girls should be taking these sorts of risks. In fact, Dr. Kane urges parents not to worry about their daughters any more than they worry about their sons:
"Do not give daughters any image or message that they simply cannot measure up physiologically and that it's important for them to remain second class citizens in sports," Kane warned. "That again just simply reinforces all of the ways in which women have been literally and figuratively kept on the sidelines in sports."
Four months after her most recent concussion, 13-year-old Meghan Tarr returned from the sidelines, not entirely without trepidation.
"I was scared," Meghan said, "but then after one game I got all better and it was fine again."
Meghan says her brain now feels 100 percent recovered, but for the first time in her life, this "active since birth" girl finds herself having to rebuild her leg muscles after months of inactivity. Shannon Tarr says seeing her daughter struggle with those issues was more difficult than the concerns that come with her return to play.
"I definitely worry just like any mother would worry," Tarr said, "but there are so many things we could worry about. It's what makes her happy. She loves to play soccer and lacrosse and track, so I just gotta let her have fun."
This segment aired on June 23, 2012.