The risk of concussion is so high in bodychecking that it should be banned until hockey players are 17, says a commentary in the Canadian Medical Association Journal.

Neurosurgery professor Dr. Michael Cusimano and fourth-year medical student Anthony Marchie of the University of Toronto reviewed the findings of dozens of medical studies relating to bodychecking and brain injuries.

Bodychecking in minor hockey is a controversial and emotionally charged issue.

Proponents of bodychecking argue young players need to learn to hit to help their team and to develop their skills.

"The brain is still maturing and if it's exposed to repeated brain injury, we may not see those effects immediately, but there's more and more mounting evidence that suggests we will see the effects later," said Cusimano.

The effects of repeated concussions include permanent learning disabilities and other neurological and psychological problems.

Concussions in hockey are usually from bodychecking and are rarely the result of being struck in the head by a puck

There are expert guidelines on when players can return to play after a concussion, but Cusimano and Marchie say parents and coaches should also consider if they should.

"Physicians should counsel patients and their families about the risks and benefits of continued play and should explain the importance of being realistic about ambitions for a future in hockey ..." the pair wrote.

• FROM MAY 19, 2003: Young hockey players banned from bodychecking

In May, Hockey Canada reversed an earlier decision allowing bodychecking among players as young as nine.

Bodychecking is allowed among players aged 11 and older.

Bodychecking is the most common cause of trauma in hockey and accounts for 86 per cent of all injuries among players aged nine through 15, say the pair. They work at the Injury Prevention Research Centre at St. Michael's Hospital in Toronto.

The president of the Greater Toronto Hockey League, John Gardner, is an advocate of bodychecking. He doubts the study's figures.

"If there are that many injuries, certainly the insurance statistics of Hockey Canada don't bear it out," said Gardner.

• RELATED STORY: Bodychecking dangerous for kids, study says (CBC Nova Scotia)

The researchers concluded 17 should be the starting point for bodychecking because size differences have evened out by that age and players aren't as easily pressured into taking a risk.