Stricter rules against aggressive behavior in hockey games are the most effective way of reducing the rate of serious injuries in young players, Canadian scientists say.

A trio of researchers from the neurosurgery division of St. Michael's Hospital at the University of Toronto combed through studies to examine the effectiveness of various kinds of interventions on injury rates in hockey. In their meta-analysis, published in the Canadian Medical Association Journal on Monday, they reviewed 18 studies conducted in both the U.S. and Canada. Some papers assessed the effectiveness of changes to league rules on bodychecking; others looked at educational and behavioral interventions.

"We found that interventions based on rule changes showed the greatest likelihood of making ice hockey safer for youth," the authors wrote.

Mandatory rules against aggressive play, including things like the banning of bodychecking, resulted in an average decrease of between one and six penalties per game and injury rates decreased by anywhere from three- to 12-fold, the authors found.

Educational interventions, such as informative videos or coach training programs, also showed signs of reducing penalties, but the studies that examined these approaches did not specifically examine injury rates.

Serious brain and spinal cord injuries in hockey seem to be on the rise over the last 15 years. Previous work from one of the authors, published in the journal Neurosurgery Focus in 2010, followed 67 male players from 16 to 21 years old over the course of one junior ice hockey regular season. The researchers found that the rate of game-related concussions during that 2009-2010 season was seven times higher than than the highest reported rate in the 1998–1999 season.

Other studies have found strong evidence for links between unchecked aggression and injured players.

"Hostile aggressive acts ... were the primary cause of injury in one-third of games in which an injury resulted. Among high school students in Minnesota who played varsity ice hockey, those who played to relieve aggression were four times more likely than other players to experience a concussion," the authors wrote. "These findings highlight the association between aggressive behavior and injury in ice hockey."

Rule changes may work better to bring down the injury rate, because they clearly define what is and what is not appropriate for everyone involved -- players, coaches, parents and officials, the authors said.

Another more long-term approach in hockey is called the Fair Play program, which is aimed at integrating sportsmanship into the criteria that affect a team's final standings in a season. Under this program, teams get points for staying below a certain limit on number of team penalties per game. Some critics have called for removing penalty quotas, as it may encourage teams to “use up” their allotted penalties.

The authors of the current study suggest that using sportsmanship criteria in conjunction with stricter penalties for more serious infractions, such as bodychecking from behind and hitting players in the head, could improve the overall effectiveness of interventions like the Fair Play program.

“The Fair Play Program is already an accepted part of a minority of hockey organizations, so it could be a means by which to ultimately alter hockey culture,” the authors wrote.

SOURCE: Cusimano et al. “Effectiveness of interventions to reduce aggression and injuries among ice hockey players: a systematic review.” CMAJ published online 3 December 2012.

Canada