She started getting terrible headaches, dizzy spells, draining fatigue and nausea. She took two weeks off school, unable to look at screens, read her textbooks or complete her class work. It would take a full school term to return to her studies full-time. "I couldn't remember what I just read on a page, and I'd really struggled to grasp concepts," she said. She missed the soccer season. Every time she tried to get back on the field, the sick feeling returned. "I wasn't really myself. I was quieter and sadder. I wasn't as fun and energetic [as I had been]," she said.

Brigid, now 17, is fully recovered and in year 11 at Ascham School. The aspiring soccer player is back on the field and a staunch supporter of the girls' school's new concussion management policy. Girls from Ascham School play touch football at Double Bay. Credit:James Alcock Emerging evidence suggests female athletes are more likely to suffer concussion from less brutal blows, and report more symptoms, than male athletes. Most concussions don't result in loss of consciousness, making them difficult to detect.

"We realised we really needed to look at this more seriously," Ascham's head of sport Stuart Hanrahan said. He began researching concussion and enlisted the help of HeadSmart, a sports program that offers education and tools to help organisations assess and manage concussion. "It was a really fascinating project, learning about how sports codes and teams managed concussion and tailoring it for our school environment," Mr Hanrahan said. The policy does not expect coaches to diagnose concussion from the sidelines. "We took diagnosis completely off the table," he said.

Instead, the school has a strict policy: if a student sustains any knock to the head, she comes off immediately and doesn't go back on for the rest of the game. Loading The move hasn't been universally popular. "Parents want their kids to get back in the game. But I'd much rather have an angry call on Monday morning saying, 'You didn't let my daughter back on the field' than 'You let her back on and now she's in the emergency room.' " Adrian Cohen at the University of Sydney and director of HeadSafe - a concussion research, education and advocacy group - said the NSW Department of Education concussion guidelines were "very vague and generic".

The concussion advice under "further information" in the sports safety guidelines advises schools to look immediately for "a bump to the head or body" and, if concussion occurs, the student should stop participating immediately and can only return to sport once all symptoms are resolved and with medical clearance. A spokesman for the NSW Department of Education said the guidelines were written in consultation with the Office of Sport, and community sporting organisations including the AFL, NRL, Rugby NSW and the Sydney Children's Hospital. Loading Replay Replay video Play video Play video Staff at Ascham use the HeadSmart FirstResponder app to assess whether a student may have a concussion. All students with a suspected concussion are referred to a medical practitioner. The school has partnered with a local concussion specialist, to whom they send the most serious cases, including a 13-year-old student who hit her head on a high jump bar at the school's sports carnival.

The student returned to school with a GP's medical certificate to cover a few days off school. Mr Hanrahan was not satisfied and sent her to the specialist. She had fractured her skull. "That really could have been catastrophic," Mr Hanrahan said. There have been about a dozen suspected concussions since the policy was introduced in June. "We averaged two 'head impact incidents' a week and we investigate about half of those as concussion," he said. Ascham's return-to-learn procedure stipulates students cannot return to play until they are back in class full-time.

The school also uses HeadSmart's baseline test to measure students' reaction time, memory, speed of mental processing and executive function. If they sustain a suspected concussion, they take the test again - sometimes several times over the days and weeks following the head knock - to watch for possible impairments and improvements. Girls from Ascham School play touch football at Double Bay. Credit:James Alcock "It's our final line of defence," Mr Hanrahan said. Dr Cohen has called for Australia to introduce legislation that would make it illegal to send a young player back on the field with suspected concussion. The US and Canada have enacted such laws: the US Lystedt Law and Canada's Rowan's Law are named after a teenage boy and teenage girl who died after sustaining concussions and returning to play.

"We need to do something about this before we have someone to name a law after," Dr Cohen said, citing the deaths of four Australians under 30 in the past two years linked to concussions, including Margaret Varcoe who sustained a head injury in the women's grand final of the South Australian National Football League. Loading He was particularly concerned that girls' sports had a "lower level of scrutiny" that heightened concussion risk. "There's a looseness in girls' sports, with younger, less-experienced referees who are more open to abuse and being screamed at or influenced by players and spectators. The play is also looser, with more flinging of arms and late, high tackles, and not much training in avoiding being hit," he said. "We have a situation in Australia where a kid can get injured at a club Aussie rules game on a Sunday and turn up for school rugby on a Friday."