For the past seven years Dylan Cleaver has been at the frontline of reporting on sports-related concussion and its effects. His research has led him to agree - reluctantly, at first - with the world's leading experts who say children should not be exposed to contact sports. In the first of a three-part series on the science behind sporting head injuries, he explains what changed his mind.
There would have been a time, not that long ago in fact, when I would have dismissed the idea of banning contact sport for children as crazy talk.
I would have described it as a gross overreaction to a problem for which we still don't know all the questions, let alone the answers.
Yet the more I learn, and the more I think about the idea of sport and everything it should represent, from greenshoots to grassroots to the top of the professional tree, the more I believe we're seeing the last days of pre-teen contact sport.
It just makes too much sense.
This is not about "political correctness", "wrapping kids in cotton wool", "coddling them" or any of those easy, meaningless refrains. The innate curiosity of children ensures they will get themselves into scrapes and unsafe situations. In the playground, they're going to organise themselves into impromptu games of rugby and bullrush, and mimic WWE wrestling or whatever Xbox game is de rigueur - just as it always was.
But there's a crucial difference between everyday rough and tumble and organised situations where we are potentially putting children's future health at risk. That difference is choice. Real choice, not choice shaped by the most influential of all drivers in children - wanting to please their parents.
Nearly all the important markers for neurodevelopment, or brain function, occur between the ages of eight to 13, including the organisation of sensory, motor and cognitive function networks. There is evidence to suggest that head trauma at this age interrupts this evolution.
A paper from Boston University titled "Youth Exposure to Repetitive Head Impacts (RHI) from Tackle Football and long-Term Neurologic Outcomes" acknowledged the limitations of current research, but concluded: "There is growing evidence that exposure to RHI in tackle football during youth is associated with a variety of short- and long-term changes in cognition, behaviour and mood, as well as structural changes to the brain."
A study of 214 former American football players showed marked increases in cognitive dysfunction between those who played tackle football before the age of 12 and those who played after (although, intriguingly, the degree of tauopathy wasn't related to age exposure - but I'm getting ahead of myself here).
The study was not well received.
"In this country American football is part of our blood and there's so much pressure everywhere to keep tackle football going," says Dr Robert Stern, Professor of Neurology, Neurosurgery, and Anatomy and Neurobiology at Boston University.
"When we publish papers that suggest that starting to play tackle football before age 12 might not be good for you, that goes against so many people's dreams and beliefs. It's a cultural issue."
Likewise, any suggestion rugby and league should remain contactless until high school, and football should be a ground-based game only, will be met with contempt among many.
There are also fundamental differences between American football and rugby, league and heading a soccer ball that cannot be discounted: most notably the use of a helmet that encourages children on the gridiron to lead with the head.
There are still enough jarring impacts in helmetless contact sport, however, to raise concern.
Even if we didn't know about the debilitating effects of chronic traumatic encephalopathy (CTE), the disease that lurks behind contact sport head injuries, my thinking might have moved in this direction. Having talked to those who are suffering and to those working to solve the puzzle as to why some athletes will deteriorate later in life and why many more won't, it seems a no-brainer, to abuse a horrible pun.
The science around CTE is evolving fast. Way too fast for many in the contact sport community and, also, far too fast - some would say recklessly - for many in the medical science community. But it does seem to be moving in a consistent direction: the cumulative effect of subconcussive hits are the mortal enemy of contact sport athletes.
Don't take my word for it, listen instead to people like Stern, a neuropsychologist who has spent the bulk of his career as an Alzheimer's disease researcher and clinician. He has been tasked with setting up trials and studies to detect CTE - which can only be diagnosed post-mortem - in the living.
"Every step of the way we have learned something powerful and new," he says.
"When we started we were sure that the development of CTE required big, symptomatic hits – concussions. When we started seeing people who had none of that history but had extensive exposure to repetitive head impacts, the subconcussive hits, it changed everything for us.
"Then we started seeing the disease in brains of younger people, not just older football players."
Stern, along with peers such as doctors Bob Cantu and Ann McKee, are adamant there is no such thing as safe head trauma, no matter how benign it might look. Their research suggests those who started taking head knocks younger are more susceptible to brain diseases and less resistant to conditions that impair cognitive function.
If you could dramatically reduce the rates of later-life problems in athletes by removing collisions from sport in under-12s, why wouldn't you do it? Other choices with risk elements, such as smoking and drinking alcohol, are age restricted. Why wouldn't smashing into another human be put into that category?
To get there, obviously, would require a quantum shift in culture for New Zealand, where, according to 20th century prime minister Richard Seddon, the very embodiment of colonial "manhood and virility" was demonstrated through rugby.
I feel uncomfortable writing this in the first person. I have been tested twice for concussion, once after missing a hook shot while batting helmetless (stupid), and once when falling off my bike at night while riding without lights (stupider). Both times I was bruised and embarrassed, but not concussed.
So I have no personal attachment with the syndrome. My connection to concussion has been through the voices of others, and I have found those voices compelling.
I recall the first time I talked to a high-profile player specifically about what concussion had done to him. Rugged lock Paul Tito was first dazed, then knocked out when taking two hits within seconds while playing for Cardiff Blues.
He was out of the game for a month. Tito was unable to drive because of blurred vision; unable to do even light exercise without a blinding headache; unable to watch television for more than short bursts; and unable to even communicate effectively with his wife and young family.
What Tito knew also but had failed to disclose at the time was that he'd received three "bad head knocks" in the weeks leading up to that fateful game, but never reported them.
"If you stop for every injury you have, you wouldn't play often," he said. "I think that's every [player's] attitude."
That was not pre-professionalism, when rugby's macho culture was best represented by the fact a player was not allowed to be replaced unless a doctor had declared him medically unfit to continue. It wasn't even the noughties, when we'd still laugh at the sight of clearly concussed players wobbling around the field after catching one on the noggin.
This was 2012.
The series I wrote, called the Knock-on Effect, covered a lot of ground. Rob Allen - brother of All Black Nicky Allen who died after receiving a traumatic head injury in a club game in Australia - talked about his belief that rugby officials were "laundering" the risks of concussion to their players. There was also a heartbreaking hour on the phone with Karen Walton, the mother of Ben Robinson, a 14-year-old Northern Irish boy who succumbed to head injuries received while playing a junior schoolboy match.
But looking back, much of the reporting, no matter how earnest, was naive. The overarching conclusion was that as long as there was a culture shift away from the macho bullshit of shake-it-off-and-carry-on, then most of the problems would be solved.
The science was very much secondary.
My next deep dive into the fog-filled world of head injuries began as a human interest story about Neil Wolfe, a man I'd admired as a kid, who was suffering from early onset Alzheimer's disease. His family wondered whether numerous head injuries accumulated while playing for Wellington, Taranaki and the All Blacks contributed.
That human interest story quickly morphed into something much larger than I had anticipated when it turned out a cluster of players from the same place - the same team even - were suffering from dementia.
Once the stories started rolling it took some time before they stopped as more and more families contacted me to tell me their tragedies.
It brought crashing home the idea that concussion, or more specifically the long-term effects of concussion, wasn't just an abstract concept. This had the ability to destroy lives and to uproot the foundations of family.
The media is often accused of getting ahead of the science when it comes to concussion and this is both true and unfair. By and large we are not scientists or even science writers. I'm certainly not. I'm a sports reporter with only a passing interest in the match and a deep fascination with the humans who take part in it.
Where I concede I over-reached was my assertion that the individuals I identified as suffering from a range of dementia illnesses were just the tip of an iceberg.
In doing so, I made a clumsy connection that because it was happening in American football, a contact sport, it made perfect sense that it would inevitably happen in other contact sports, like rugby and league. This discounted factors possibly unique to American football, such as the type of hits (for example, linebacker to linebacker hits are far more frequent than rugby tackles), training methods and environmental factors such as widespread steroid abuse in US sport.
It became clear I needed to learn more about the science.
So I went to Boston.
The Alzheimer's Research Centre at Boston University is difficult to find, even with the help of a map. You take a right there, a sharp left here, past one elevator bay to the next, up a few floors, right, then through some unwelcoming double doors, another left and if you're lucky you might be in the vicinity.
It's like they don't want to be found.
But once there, you find a passionate bunch of experts fighting for the same thing: to understand the complexity of diseases that rob humans of their life in the most soul-destroying way possible, by first stealing their mind.
Chronic traumatic encephalopathy is a relatively new disease on the block but it has tended to hog the limelight.
"We're all Alzheimer's researchers," says Dr Lee Goldstein, who believes he has found the mechanism that causes CTE.
"I don't have nearly the confidence on Alzheimer's disease as I do on CTE. We have a pretty good bead on CTE. We've already developed interventions that will stop the disease. We're well down the road on diagnostics and all sorts of other things. This has been relatively rapid. We have a very good idea of what's going on [and] not just in American football and rugby."
The ideas they have are leading them to say the cost-benefit analysis of pre-teen contact sport does not add up. It leads them there not because they're wishy-washy liberals, but because they're scientists.
Never thought I'd say this, but I'm with them. Whereas I once believed all contact sport needed was a change of culture, an attitude shift, I now realise that without it being aligned to science, it is only attacking part of the problem.
The culture shift was actually quite easy. The speed in which it was implemented here was admirable. Tito's attitude less than a decade ago would almost certainly put him in an outlier category today - and he'd be the first to concede that.
Even those who feel most cynical about New Zealand Rugby would concede the organisation has been at the forefront of raising awareness of the dangers of concussion through programmes such as RugbySmart and the blue card system.
The smartest move for them to make now, I believe, is to be bold: decree rugby a non-contact sport until high school.
All the benefits that kids accrue from team sport - camaraderie, discipline, work ethic, fun - will still be there. Tackle technique and preparation for contact could still be coached in pre-teens.
None of the health benefits from exercise will be compromised.
I concede, willingly, that there is an arbitrary element to an age limit. It is difficult to make a case that something that is inherently dangerous at 12 is suddenly safe at 13. I'd put my hand up, too, and admit that there is an irony in wanting to learn more about the science while suggesting something based on uncertain, ever-evolving science.
I'd also suggest, I would hope more persuasively, that it is better to do something than nothing at all. If pre-teen head impacts cost more than those suffered later, I'd rather be too safe than too sorry.
As Dr Ann McKee, the neuropathologist who has identified CTE in the brains of hundreds of former sports stars says, the benefits of sports for children are profound, just as the development of motorised vehicles were for shrinking the world.
"But we don't put our kids in cars without seatbelts."
* This series was made possible through an nib health scholarship.