Rule changes change the culture of hockey by defining acceptable behaviour, doctors say. (Bruce Bisping/Star Tribune/Associated Press)

Restrictions on bodychecking in minor hockey can help reduce injuries, a new Canadian review suggests.

A change in rules to limit bodychecking could reduce harm to young players, neurosurgeon Dr. Michael Cusimano of St. Michael's Hospital in Toronto and his co-authors concluded in Monday's issue of the Canadian Medical Association Journal.

The researchers reviewed 18 articles on reducing aggressive behaviour in the sport. Of those, 13 involved players under 18 in Canada and the U.S.

"Clearly the bodychecking is contributing to the injury rate," Cusimano said. "If you can institute a rule that can lessen that then you're bound to reduce injuries."

Brain injuries account for an estimated 15 per cent of injuries among players aged nine to 16, previous studies suggest.

The study's authors aimed to synthesize what's known about reducing hockey injuries to suggest a path forward.

"We need to have that open discourse and to start to talk about what we need to do to make it fun again for kids to play hockey and [be] safe," Cusimano said.

He noted that the number of children registered to play hockey is down and it tends to drop off as aggression comes into the game, but none of the studies addressed attrition.

Fewer aggressive penalties

Cusimano said that in his practice he sees both the short-term and long-term effects of brain injuries. In the long-term, players may look fine, but lights and noise can bother them, or they may have trouble following along in class or concentrating.

The review also looked at the effectiveness of educational programs in hockey, such as the Think First videos to inform players, coaches and parents about recognizing concussion symptoms and removing players from games when necessary.

The educational programs were associated with declines in aggressive types of penalties, such as cross-checking or pushing a player into the boards from behind. But those studies didn't include enough players to determine if injuries declined.

Critics have argued that teaching children to bodycheck at an earlier age helps them learn to protect themselves, but that assumption isn't borne out by the data, Cusimano said.

He stressed the need to change the culture of hockey, adding that introducing and enforcing rule changes are one way to do that quickly.

The experience of the New Zealand Rugby Union suggests that a combination of rule changes and mandatory educational programs nationwide helps reduce brain injuries, the researchers said.

Cusimano also suggested changing the governance in minor hockey, such as limiting how long people can serve on boards, involving more women and allowing children to have their say.

The review also included studies on cognitive behavioural interventions, such as training on managing aggression, which focused on individual players.

Athletes participating in the studies weren't randomized and the reductions in injuries were associations. Other factors could be contributing, and no cause-and-effect relationships could be drawn.

The studies reviewed also did not consider the feasibility of the changes.

The research was funded by the Canadian Institutes of Health Research Strategic Team Grant in Applied Injury Research in partnership with the Ontario Neurotrauma Foundation.

With files from CBC's David MacIntosh