But the reason why he plays memory games with his wife and children and occasionally wakes up in the garage panicked and confused is the reason why his concussion story is important.

"It will get me at some point and probably will [take years off my life]," former ACT Brumby and Brisbane Bronco Ryan says.

"I had a fair few head knocks over the years because of the way I played.

"I'm trying to do everything I can now to minimise the effects in the future. So playing memory games, brain training off my own bat.

"It does make you a bit sad to think I could have some sort of issue with my melon at some stage. It definitely worries you, you never want to be a burden to your family. But you can't blame anyone, no one knew."

Former Canberra Raiders lower-grade player Andrew Heffernan feels the same responsibility after a head knock ended his career in England last year. Heffernan is still suffering symptoms 15 months later.

"My last concussion was April 7 last year and I'm still having those symptoms every single day," Heffernan said.

"The vertigo and disorientation with where you are is probably the biggest one for me.

"The testing is very neuro-cognitive based. That's only my opinion, but the research has backed it up as well that there's a need for a more holistic test which covers each of those [brain] systems.

"I slipped through the cracks in some respects. If it comes up the first time I've damaged the vestibular system, my [quest to] return to play is completely different.

"I've done the research now and I want to keep educating people and these conversations spark investigations into what we need to do differently.

"I don't blame anyone at the medical staff there [Hull KR], they were just following protocol, but long term we have to get that protocol right and we'll get there."

Ryan is the no nonsense tackling coach who carved a career out of his hard-hitting defence, first with the Broncos and then with the Brumbies.

He was the first player to win NRL and Super Rugby titles and is now one of the most respected defensive coaches in Australian sport.

But behind the scenes Ryan is preparing for the biggest hit of his life: chronic traumatic encephalopathy - better known as CTE. It's a degenerative brain disease caused by repeated head injuries.

The impacts of the disease have been known for some time in American sport, highlighted by an NFL payout to former players expected to hit $1 billion in the coming years.

Australian sport has been relatively shielded from the CTE debate, although concussion protocols have steadily improved over the years.

But rugby league was rocked last month when a study found the disease in two former first-grade players who had played more than 150 games.

Ryan wasn't surprised. He has been dealing with symptoms since his days as a tackling machine in rugby league and union.

The symptoms range from memory loss (be it games he's played in or conversations he's had), anxiety, being uncomfortable around crowds and, most recently, waking up in the front yard, kitchen or garage at his Sunshine Coast home.

He has thought about donating his brain, like Peter Sterling says he will do.

MORE SPORT

But Ryan prefers to channel his energy into positive areas rather than dwelling on the past or what could happen in the future.

That's why he takes great pride in his role at the Queensland Reds teaching modern-day players a tackling technique to help them avoid the head injuries he suffered.

Or speaking to concussed players to reassure them it's better to miss a game than to risk long-term damage.

Or exercising his brain at home with simple games in the hope it will reduce concussion effects in the coming years.

"I couldn't put a number on [how many concussions]. Maybe eight or 10 fully comatosed when you're running on robot mode on the field," Ryan said.

"But the consistent, smaller bumps were the worst because they happened all the time. During the game I'd get a sort of tunnel vision, which was like looking through broken glass.

"Some of the symptoms haven't happened for a long, long time now. I suffer from a bit of anxiety and panic attacks. It's gotten worse over the last few years, now I understand it's off the back of concussions in the past and I can deal with it.

"What's happened to me in the past is unchangeable. I'm in the mindset of staying positive and trying to reduce the effects.

"I want to stay healthy physically and mentally. There are too many people in the world feeling sorry for themselves for one reason or another.

"I refuse to be that person."

Concussion in Australian sport has become a major area of concern for players and officials over the years as more research and evidence emerged around the world.

Two NRL referees were dropped this week after failing to stop a game to deal with a concussed players. Their failure came just weeks after rugby league was shaken by the findings after analysing form players' brains.

The discovery of brain trauma in two former players shook rugby league.

CTE can only be diagnosed via autopsy and is associated with depression, mood swings, short-term memory loss and dementia.

The NFL has already paid more than $US500 million from about 2000 claims lodged by former players and the figure is expected to rise to $US1 billion.

Ryan, who spent four years as the Brumbies' defensive coach before returning to Queensland this year, believes Australian sport is moving in the right direction to make people more aware of the dangers.

The AIS and Sport Australia launched an updated concussion document earlier this year to give athletes, coaches and parents guidelines to better recognise the dangers of head knocks.

Sport Australia was targeting amateur and junior competitions, AIS chief medical officer David Hughes declaring: "children's brains are worth the wait" when detailing a return to play protocol.

"Children take longer to recover from concussion than adults," Hughes said.

"Concussion in Sport Australia believes any child 18 years and under, who suffers a concussion, must not return to play until they have been clear of symptoms for 14 days.

"We believe this is an important step forward to ensuring Australians at all levels have access to the most up to date and accurate information on concussion."

A study for the medical journal Brain in 2012 detailed autopsies of 85 donated brains, mostly American professional athletes, and revealed the majority had brain tissue clogged with a protein linked to CTE and repeated trauma.

But there are still so many unknowns, especially in Australia where there had been no official links to CTE until the analysis of two former players' brains last month.

Ryan, who was keen to work with NFL teams to improve their tackling technique, hopes his story, and the growing knowledge about concussion, will not deter people from playing contact sports. He hopes it will encourage better coaching.

"I coach people to tackle lower than what I did. For me, I tackled higher because it gave me more crunch value," Ryan said.

"But I don't coach that, I coach to attack the middle of the body which is the softest part. There's a small margin of error. What we're after is the [area] of hips to ribs - the centre of gravity.

"Any kid I've ever coached who gets a knock at training, you've got to take them out straight away.

"If I see someone get a bump at training or in games, I've pulled them aside and said life is too short to be worried about being picked in the team the next week.

"The protocols are there for a reason. As much as you want someone to play because of their ability, you can't afford to risk it. I refuse to risk it.

"The attitude from the national bodies have improved. But it also has to be about teaching tackling, and it has to be from the national level to the coach of under-7s. If you're going to coach, you must be proficient in the technical terms to reduce it from kids.

"We didn't recognise the symptoms in the past and there have been players die because of mentally-related issues.

"Ultimately you want to improve the game with your coaching.

"But I still love, I still love that my thing about rugby league or rugby union was the contact. That's the game for me."