Research out of the United States is raising questions about head injuries in young female athletes.

According to the Women's Sports Foundation, high school girls experience sport-related concussions at a much higher rate than boys — double or triple the rate, depending on the sport.

At Calgary's Edge School, which specializes in athletics training, head athletic therapist Brady Greening says the students' games are monitored closely.

"They're constantly watching for big hits, constantly watching for symptoms of pain, of headache, or if they're out of it and not playing well," she said.

Greening says when it comes to concussions, she doesn't see any gender differences.

"I see everything. I see them with boys and girls equally," she said.

University of Calgary neuropsychologist Keith Yeates says the U.S. research raises a lot of questions.

"It's still a phenomenon not everyone is necessarily convinced is real," he said.

Yeates says it's not known why the rates appear much higher for girls, but thinks girls may report their symptoms more readily than boys.

Other experts speculate the reason could be that girls are more susceptible to concussions because their necks are weaker.

"If it turned out that girls were more at risk for concussion in a particular sport because of neck strength, then perhaps we could work on providing them with exercises and so forth that would help build up their neck strength," he said.

University of Calgary researchers are doing their own studies to determine why girls experience sport-related concussion symptoms for longer than boys.