The risk of concussion in certain high-impact sports seems so glaring that Dr Bennet Omalu cannot believe he is still trying to beat the evidence into the heads of naysayers.
But that is exactly the predicament the Nigerian-born medical doctor faces even to this day, more than 13 years after he first diagnosed Chronic Traumatic Encephalopathy, or CTE, in several dead National Football League (NFL) players.
"I am not anti-sports," he stressed in a phone interview with The Straits Times arranged by cinema operator Golden Village.
"But high-impact sports like football, boxing, ice hockey, mixed martial arts and rugby are dangerous for our children," added Dr Omalu, now an American citizen and the chief medical examiner of San Joaquin County in California.
"There are hundreds of alternatives. Instead of a helmet, give a child a racquet."
It is a similar message to the heartfelt plea titled Don't Let Kids Play Football the 47-year-old penned in last month's New York Times op-ed pages.
Last September, United States-based researchers identified the degenerative disease CTE - widely believed to stem from repetitive trauma to the head, leading to conditions such as memory loss, depression and dementia - in 96 per cent of former NFL players that the lab had examined.
A settlement, approved last year by a federal judge, could cost the league US$1 billion (S$1.42 billion) over 65 years with roughly 5,000 former gridiron players who have sued it over past head injuries.
Dr Omalu's battle to study and publicise CTE in the face of opposition from the NFL is brought to the big screen in the movie Concussion - he is portrayed by Hollywood star Will Smith - which opens in Singapore this week.
The 122-minute medical drama has been tipped as a contender at next month's Academy Awards but for Dr Omalu, who has seen the film at least six times, its impact was felt much earlier. He said: "Many nights I wept and I wished I never came in contact with traumatic brain injury...
"But what made me continue was when I realised that the retired players were suffering in silence, in obscurity.
"There was nobody to speak for them, in fact they were ashamed of themselves thanks to the culture of machismo pervasive in the NFL."
Even the Beautiful Game, or soccer as the Americans call it, was not spared from criticism by Dr Omalu. At the 2014 World Cup in Brazil, Uruguayan Alvaro Pereira was knocked out after being accidentally hit in the head by England's Raheem Sterling.
Pereira was later allowed to continue playing.
"I wouldn't classify soccer as a high-impact sport. The aim of the game is not to hit your opponent. But there are some areas to consider."
Added the father-of-two: "Instead of 11-a-side, can we reduce the number of players on each side and lower the risk of collisions? Can we take out heading in youth competitions?
"It's about management of risk and how we can minimise repeated trauma to the head. It's about evolving our attitudes."
Last November, US Soccer, the governing body of the sport in the country, banned heading for children aged 10 and under while those 11 to 13 would have headers limited in training.
Comprehensive precautions are taken in Singapore to ensure the safety of players, noted Singapore Rugby Union (SRU) general manager George Danapal.
All SRU league games, tournaments and training by the national men's and women's squads are accompanied by an ambulance service provider that has been trained according to the concussion regulations of World Rugby.
Noted Danapal: "We follow these guidelines very strictly."
Added Dr Omalu: "This was never about the NFL or football... But what are we doing for our children to educate and teach them.
"In the past, the majority of parents claimed they were unaware of the inherent risks in high-impact sports and repeated blows to the head.
"Now we know its harmful effects and it is our duty to protect our children."
Concussion opens in Singapore tomorrow.
This article was first published on January 13, 2016.
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