Dr. Michael Cusimano of St. Michael's Hospital and his research team reviewed 18 studies that evaluated interventions aimed at reducing aggression-related injuries; 13 of them looked at mandatory rule changes in minor hockey in Canada and the U.S.
Eleven of those studies found rule changes resulted in one to six fewer penalties per game, while cutting the number of injuries three- to 12-fold.
"We know that rules automatically say what's appropriate within a culture," Cusimano said. "If we have rules and they're enforced, then we see changes."
Brain injuries like concussions often result from aggressive bodychecking and account for 15 per cent of all injuries to players aged nine to 16, says the study published Monday in the Canadian Medical Association Journal.
On some teams, a single season can see up to one-quarter of players sustain a concussion, a traumatic brain injury that typically results from a blow to the head. Symptoms include headache, confusion, memory loss, dizziness and nausea or vomiting.
Depending on the severity of the concussion, symptoms can last for days, weeks or months. Concentration and the ability to remember may be impaired; the person can be irritable, depressed and experience marked personality changes; sensitivity to light and noise, along with disturbed sleep, are also common.
With repeated concussions, the brain can be permanently damaged.
"Given that brain injuries are so common and that they can have permanent effects, we need to introduce measures that we know have been shown to work to reduce the numbers of children and youth suffering these injuries in sport," Cusimano said.
Educational programs and behaviour modification interventions also have a part to play in curbing aggressive actions that can lead to injuries, but studies suggest they are not as effective as rule changes that dole out punishments for infractions.
"Rule changes essentially alter the culture of a sport and clearly define acceptable behaviour for players, coaches, parents and officials," Cusimano said.
But rules aimed at preventing injuries also need punitive teeth behind them to make them stick, he said.
"If there were financial implications, whether (teams or leagues) losing insurance coverage or lawsuits or whatever mechanism there is, then I think things would start to change."
While the issue is "constantly reviewed," Hockey Canada has no plans to change current checking rules, said Paul Carson, vice-president of hockey development.
The national body permits bodychecking at the Peewee level, which includes players aged 11 and 12, but provinces can choose to tighten those rules, he said. Quebec, for example, has raised the age when bodychecking is allowed to 13- and 14-year-old Bantam players.
"I tend to think bodychecking as a skill is different than bodychecking as a tactic, which then becomes that aggressive play," Carson said Monday from Calgary.
Last season, the organization instituted a rule of zero tolerance for head contact, with double-minor penalties for an intentional contact with a player's head, even a glove in the face to push an opponent away, he said.
"I've seen the way players have adjusted to that rule, so a rule emphasis and rule change can have that kind of influence," Carson said. "But it also comes with education and an understanding that we have the ability to modify behaviours if all stakeholders play their roles — referees, coaches, players, parents — they all have a role to play here.
"I'm not sure if you just change the rule without the education, without good initiatives to modify behaviour, that you'd get much further along."
The Toronto Non-Contact (TNC) Hockey League was begun four years ago by a group of parents concerned about injuries being suffered by their children in contact hockey leagues.
TNC president Bill Robertson, who has 13- and 15-year-old sons playing in the league, said teams have a lower injury rate compared with teams in contact leagues.
"I think what Dr. Cusimano is suggesting is very positive and I think it is the kind of thing that we are intending to address in our league," Robertson said. There is also a focus on encouraging respect between players and coaches on opposing teams, and trying "to change the culture of the game."
"It started as a safety issue, but it's also about making the game better, and we see it in the results.... Training (our players) without bodychecking creates better hockey players, and the games are more exciting. They're fast, they're fun."
Having fun is one of the reasons that young people play hockey, agreed Cusimano, who said the sport keeps them active and physically fit, and helps them to learn social skills, "like how to be a member of a team and work together toward a goal and be punctual and all kinds of good things like that.
"But fun is right up there at the top."