It was at the North Adelaide Football Club's 30-year premiership team reunion that Kim Klomp decided to reveal a secret he has held close to his chest for almost two decades. 

Throughout the 1980s and early 90s, Klomp was a legendary Australian Rules football player.

He competed in one of the nation's top football leagues, the South Australian National Football League (SANFL), and is the former captain of the North Adelaide Roosters.

On the field, he was brave, tough and uncompromising. But his glittering football career had come at a cost.

Now middle-aged, Klomp was suffering from severe depression and suspected something was terribly wrong with his brain.

At first, he could not understand what was happening.

All he knew was that after retirement, life gradually became more of a struggle.

It started with small things.

"Even now, I've got a ringing in the ears. It's not even the ears.

"I've also got like a bulldozer noise at the back [of the head]."

Then, while pursuing a successful career in sales, he suddenly quit, deciding instead to work as a security guard because he needed a job with a lighter mental load.

"The most comfortable thing I could do was doing security, where I didn't have to make decisions anymore," he said.

Concussions treated 'like a cramp'

Kim Klomp was sitting at the Strathmore Hotel in central Adelaide with his former teammates as they shared old war stories about their time playing footy.

It was Klomp's turn to talk, and he was compelled to reveal his secret — that he tried to kill himself because he believed he had a brain injury linked to the multiple concussions he suffered during his sporting career.

"Inside, I was just feeling the need to let it [the secret] go," he said.

"When I did, it was like the world had got off my shoulders."

He likened himself to former AFL player Danny Frawley, who died by suicide in 2019.

A post-mortem examination confirmed Frawley had CTE, or chronic traumatic encephalopathy. 

"If I didn't want to have that call for help, it would've been me [who died]."

In his era, little was known about the devastating impact of head knocks.

"You get rid of the cramp, you go on.

"No one even worried about it. It wasn't an injury in those days."

Klomp vividly recalled the immediate effects of a concussion.

"We'd go on a bus to meet the opposition teams, and on the way back, I'd start getting tingling in the hands and feeling a bit funny, and then I'd start to vomit," he said.

Experts advocate for four-week recovery period

Over the past decade, researchers have focused on the link between repeated concussions and the development of the fatal brain disease CTE.

As a result, today the AFL treats concussion injuries very differently.

The rules stipulate that any player recovering from a concussion must spend a minimum of 12 days away from the game.

Neurologist Dr Rowena Mobbs is an expert in concussion injuries at Macquarie University.

She says the mandatory rest period is a step in the right direction but she is concerned that 12 days' rest is not long enough.

She says it should be extended to 28 days.

"I do commend the AFL and other football codes for extending the time players take to take to rest and recover," Dr Mobbs said.

"But the science is pointing towards possibly longer times off play and taking a conservative approach.

Dr Rowena Mobbs also warned that the AFL must be more receptive to any new research into the damaging effects of concussion.

"I think there will be a reckoning if we see the AFL and others maintain a closed approach to this issue," Dr Mobbs said.

Neuroscientist Alan Pearce agreed. He has assessed several past players' brains and diagnosed them with CTE.

He added that players in lower levels are just as susceptible to the disease as top-flight athletes.

"It doesn't matter if they play D-Grade or they're playing the AFL. A hit to the head is a hit to the head."

Dr Pearce has also questioned what evidence the AFL has based its 12-day concussion policy on.

"It has been discussed that 12 days was decided based upon a body of evidence, but many of my colleagues are unsure of what that is," he said.

In a statement to 7.30, the AFL defended its policy, saying it was "not aware of any reputable science or 'evidence' that any specific period of absence provides any such certainty or guarantee of safety".

It also clarified that the current "mandated 12-day rest period is a minimum period", noting that when a player does return to football it is ultimately up to the "clinical judgement of accredited AFL club doctors" and "nothing in the guidelines compels a doctor to return a player to contact play after only 12 days".

The AFL also emphasised that "protecting the health and wellbeing of all people who participate in our game is the highest priority for the AFL and we take concussion and the protection of the brain health of all those playing our game extremely seriously."

The broader impact

Investigative journalist Michael Warner recently penned an award-winning book about the AFL, titled The Boys' Club.

He is concerned that the AFL has not considered the bigger picture.

"The issue that I see for the AFL, Australian Rules as a code, is what about the lower levels of the game — suburban levels, the junior levels? Where's the game going to be in 50 years' time? And I think the answer to that is, 'In a very different place.'"

He also predicted the league could be held liable for past injuries suffered by ex-players.

"I don't think there's any doubt that somewhere down the track, the AFL is going to have to pay out a lot of money — tens of millions, if not more — to former players who have endured head knocks," he said.

Back in Adelaide, Kim Klomp is just grateful for the support of his family.

He said his teammates have also been supportive since he revealed he was suffering from a brain injury.

"At the end of the day, what's helped me most has been a beautiful wife who has stuck by me, and we have a beautiful dog that we got from the RSPCA three years ago," he says. 

"They've been my lifeline. Without them, I wouldn't be here now."

Klomp is in a unique position. Because he never played Australian Rules football at the top level, the AFL, he is exempt from any future payout to ex-players.

He said neither the SANFL nor the AFL have contacted him to offer support — but all he wants is for today's athletes to be spared from the pain he's experienced.

"Anything that can be done for your brain, as soon as that happens, the better off people will be."