Dr Alan Pearce is at the front line of Australian concussion research.
"It's an issue right across the board at all levels of sport."
And not least for rugby league.
"Then watch this .. bang... it's a shoulder that's picked up him on the chin."
League is a physically demanding sport where big hits are the norm.
So too is concussion.
Dr Pearce says the long-term effects are still poorly understood.
"Australia needs to be doing a lot more research and getting funded for this."
Dr Pearce sits on the Australian Athletes Alliance Concussion Working Group set up last year.
His latest study seeks to fill the knowledge gap by focusing on changes in brain function rather than brain structure.
Dr Pearce tested 25 retired NRL players all with a history of concussion.
The players were all around the age of 50.
He says the results were alarming.
"There was an across-the-board drop in performance in the cognitive and motor tests that we did."
Dr Pearce's study focused on three areas of the brain which are particularly affected by concussion.
The frontal lobe which is important for attention.
The dorsolateral pre-frontal cortex, important for memory.
And the motor cortex, connected to dexterity.
"Their memory was impaired and also their ability to maintain attention, so trying to stay focused on a task was very difficult or more difficult for them, even though generally they're leading normal, everyday lives. The other thing about it is they're relatively young still, they're 50-51 years of age, so it could be a first indicator of anything later on."
Dr Pearce also used magnetic stimulation to test the retired players' brains.
"Our brains are working on exciting other nerves but also inhibiting so it's a balance and that balance is disrupted particularly with the guys who've had a history of repetitive head injury."
Dr Pearce's research is under peer review and will be presented at the World Congress on Brain Injury in the United States later this month.
He says what's needed now is more Australian data, adding there's an over-reliance on research from American Football.
But Ian Prendergast, from the Rugby League Players Association, believes hurdles remain.
"There's not too many people who want to be the pin-up boy or the poster-boy for concussion, for obvious reasons, there's negative connotations around the impact that it may be having on their life, post-football."
But he says, with the NRL's concussion policy in its fourth year, attitudes are changing.
"As we better understand it and we provide improved support, people will be more comfortable talking about it, and the impact it's having on their life, because clearly that the most compelling education you can deliver."
