There's been a lot of research on the effects of concussion in recent years, but the focus has largely been on high school and professional athletes. In most of those instances, boys are the target of inquiry.
A new study by researchers at the University of Washington looks at younger players and it involves girls.
Dr. John O'Kane,a UW associate professor and lead author of the study, says the rate of concussion they saw in middle school-aged girls is higher than that of older athletes.
Girls between the ages of 11 and 14 saw a 13 percent concussion rate each season. There was an average of 1.2 concussions per 1,000 athletic hours.
In May of 2009, the governor signed the Lystedt Law. The toughest in the nation at the time, it requires concussion education for players under age 18 and their parents. It also requires players with concussion symptoms to get medical clearance before returning to play.
"This group does comply with the Lystedt Law," says Dr. O'Kane, "So, the parents and the kids and the coaches do annually go through and read concussion information sheets. One of the things we took away from this study is that the education needs to be a little bit more active than that."
What they found after studying 351 players in the Puget Sound region is that girls often don't report symptoms of concussion even after having that discussion with their coach and their parents.
In part, O'Kane credits the sports culture of "toughing it out." More than that, though, he says soccer players are physically unable to play with an injured ankle or knee, but they can keep going if they're feeling a little dizzy or nauseous.
The big difference between older players and these younger girls is the support they have on a regular basis from certified athletic trainers.
"It points to the importance of maybe treating the education different with this group because they don't have the contact with the athletic trainers," says O'Kane.
He says parents should take a more active role in keeping an eye out for symptoms. He also recommends they talk with the players not just once, but several times throughout the season. They need to work harder to remind their daughters about the importance of sitting out if they feel like they might have symptoms of concussion.
Although it's rare, O'Kane says these young players are more susceptible to something called "Second Impact Syndrome." That's when a person still suffering concussion symptoms gets hit a second time. It can lead to brain swelling that can, in some cases, lead to death.
You can read more about this study in the journal Pediatrics by the American Medical Association.