A renowned sports doctor has backed calls for former AFL players to donate their brains to research, into a disease linked to repeated blows to the head.

It comes after a Victorian coroner called for more research into concussions, following an investigation into the death of St Kilda legend Danny Frawley.

The investigation found chronic traumatic encepha-lopathy potentially contributed to the depression he was suffering.

Like many AFL players, it’s likely he suffered repeated knocks to the head as a young player while his brain was still developing.

But because CTE can only be diagnosed after death, it’s impossible to know exactly when it began and when it started impacting his mood and behaviour.

Former AFL doctor, Dr Peter Brukner, told 6PR’s Liam Bartlett more players should donate their brains post-mortem.

“There is still a lot we don’t know about it,” he said.

“We still need to learn more about this condition, because it’s a very difficult condition to diagnose, to manage, and to assess what the long term impact is.”

He said more changes need to be made at grass routes levels to prevent concussions in junior sport.

“We need to have modified rules in junior sport, where you protect the head at all cost,” he said.

“We don’t want to change the whole substance of the game, but we can tinker with rules and make it safer.”

Click play to hear the full interview.

(Photo: Sydney Morning Herald.)