Minneapolis (AFP) - As the NFL continues to grapple with American football's enduring concussion crisis, safety advocates say the next frontier in curbing long-term brain injuries is to phase out tackling for children under the age of 14.
An estimated 1.2 million children aged between six and 12 years old play in tackle leagues across the United States, despite mounting evidence that points to increased risks for players who don helmets and pads at an early age.
A study published last year by the Journal of the American Medical Association discovered the neurodegenerative disease chronic traumatic encephalopathy (CTE) in 110 out of 111 brains of former NFL players.
The same report found CTE in the brains of three of 14 high school players (21%) and 48 of 53 college players (91%).
Further research by Boston University published last September found evidence between participation in youth tackle football before age 12 and impaired mood and behaviour later in life.
Chris Nowinski, the Harvard-educated former WWE wrestler who is one of the co-founders of the Concussion Legacy Foundation advocacy group, says the case of former New England Patriots star Aaron Hernandez should be seen as a warning.
Hernandez, 27, committed suicide in a Massachusetts prison last year where he had been serving life in prison following a 2015 murder conviction.
- Canary in coalmine -
When his brain was examined by researchers last year they discovered the most severe case of CTE ever found in a person of his age. Hernandez had played tackle football since the age of six.
"Aaron Hernandez's brain was as bad as guys who played two decades prior and died in their 50s. And he was in his 20s. That should be the canary in the coalmine," Nowinski told AFP.
The Concussion Legacy Foundation has launched a campaign aimed at persuading parents to avoid enrolling children in tackle football under the age of 14, something Nowinski sees as vital if the NFL wishes to safeguard its future.
"The most important thing for the long-term future of football is getting youth tackle football out of football," Nowinski said.
"The data is clear, from our perspective. Five-year-olds were never intended to play this game.
"And if we don't change that, the penalty of success will be CTE. If you play tackle football from five years old to age 30, your risk is off the charts."
The foundation's campaign has won backing from several Hall of Fame players, including Miami Dolphins legend Nick Buoniconti, a member of two Super Bowl-winning teams in the early 1970s.
"I made a mistake starting tackle football at nine years old," said Buoniconti, 77, who suffers from dementia and is suspected of having CTE. "CTE has taken my life away. Youth tackle football is all risk with no reward."
- A sport for men -
Changing perceptions about what it takes to forge a successful career in the NFL is one of the biggest hurdles in changing attitudes.
In fact, some of the sport's most iconic names, including Jim Brown, Walter Payton, Jerry Rice, Lawrence Taylor and Tom Brady, did not start playing full-contact football until they had reached high school age.
"The reason Tom Brady is playing at 40 is because he didn't have those extra nine years of being torched in youth tackle football," Nowinski said.
Nowinski believes that while players intuitively understand the risks, moves to limit tackling at youth level have met "organisational resistance" from the big business behind football.
"Football players get it. If you've been on a field and been hit on the head a few thousand times, you understand that it's bad for you," he said.
"And now we've seen so many of our friends suffer, we get that CTE is real and it destroys you and it destroys your family.
"That being said, the NFL and college football are the two most popular sports in America. People make billions of dollars a year from them and they don't want to see that change."
Nowinski believes the sport at youth level needs to be rebranded as a "game for men", noting that the evolution of children playing in helmets and pads began relatively recently, in the 1960s.
"If you look at the history, youth tackle football was not a thing until the 1960s. Before that no five-year-olds were playing tackle football. Then Pop Warner (league) became a national organisation with the goal of perpetuating its own existence and expanding across the country.
"And suddenly the kids playing the game got younger and younger. We're seeing that effect in our brain banks. The guys that started younger are worse off than the guys that started older.
"Football needs to be rebranded as it was in the beginning - as a game for men. Maybe you should be required to hit puberty before you run people over."