Tough guys get scared. Hayden Triggs broke ranks when saying as much last Monday. The players are freaked by what they are doing to each other in training on a weekly basis. They are disturbed when having to rewatch collisions already suffered in the flesh.

Leinster’s Kiwi lock was speaking about Mike McCarthy’s sickening inability to rediscover an acceptable form of consciousness in Paris last Saturday after a head clash with Jack McGrath. It’s what the cameras didn’t show, as play moved on, that was so disturbing.

Players see this all the time.

“At training, we smash each other on two days of the week,” said Triggs. “In review, when you’re watching your defence or someone else’s, you see some pretty scary things.”

The general public don’t see any of this but parents are beginning to notice from the sidelines.

Colin Doherty is a father but also a neurologist at St James' Hospital. He tells a story to highlight the radical increase in rugby collisions. Before last October's World Cup semi-final between South Africa and New Zealand he sat down with his 12-year-old son to watch the 1995 World Cup final between the same countries. "In the game 20 years ago we counted 40 sub-concussive blows – hits from the elbow upwards. In the game later that day, how many did we count?"

We guess 80

"120."

“This is an anecdotal story and not good science,” Doherty stated.

“It was an attempt to put some numbers on what all of us watching the game for the past 20 years can see; the hits are harder, they are more frequent and they are wince-inducing, as well as injury-producing. This will not prove anything. It is merely more evidence that things have changed.”

Moral duty

On his whistle-stop world tour to promote the film Concussion, Dr Bennet Omalu, who discovered chronic traumatic encephalopathy (CTE) on a Pittsburgh autopsy slab, has repeatedly stated: "We know now exposing a child to repeated blows to the head, with or without symptoms, has a reasonable risk of brain damage. It is our moral duty as a modern, civilised society to protect the most vulnerable of us."

The issue seems unending. Rob Kearney also spoke to journalists this week when promoting Laya Healthcare's new 'HEAD ON Concussion Management Programme' (whoever came up with the slogan seems wholly unaware of the poor taste in naming the initiative) which will provide 1,350 free baseline screenings to enable concussed players, or not as the case may be, from 16 and older to return to the field.

“It’s something players would have joked about maybe four, five or six years ago,” said Kearney. “‘I won’t give the baseline test my full concentration so if I do come back it will all be rosy in the garden’. It’s those attitudes that can be detrimental to the game. We’ve got much better at looking out for each other and there’s a much better degree of honesty.

“If someone was to genuinely joke and say something like that nowadays it wouldn’t be particularly well-received and guys would be turning around and saying ‘that’s not very smart’ and ‘you shouldn’t be saying things like that; younger guys hear you, that’s a not a leader’s mentality, that’s not the way to be acting.’ That’s absolutely what we don’t what schoolboys doing.

“It is an easy thing [cheating the test] but you are only going to be harming yourself further down the line.”

Kearney, who said he has suffered two concussions in his career which did not include failing a head injury assessment against Australia in November 2014, added: “From my own perspective, there is not a huge amount of difference in the collisions I was getting in international rugby eight, nine years ago as there is now.”

But, unprompted, he added: “Okay, they are more frequent and they happen more often.”

Doherty nudges us towards George Bernard Shaw’s assertion that science never solves a problem without creating 10 more. “It will never be clinically proven that multiple concussions will definably cause brain damage and dementia-like syndrome in later life. All science can do is alert, nudge, point to, suggest that there is evidence linking CTE to repeated concussion. This evidence is strongest in American football which many people feel is a totally different sport to the contact sports played here but remember they have been wearing crash helmets for 40 years.

“Also, while NFL may be a special case, it might just be the exception that proves the rule and even if the numbers of players that could be negatively impacted is smaller on this side of the world, we still have a duty to those players.”

The New England Journal of Medicine recently reported that "at least" 11 US high-school athletes died playing football during the 2015 season.

Amateur boxing has safer rules to its professional relative and American football altered their tackle rules by outlawing head-on-head collisions. World Rugby is examining their options in great detail but it’s hard to establish what rules they can alter to avoid concussive blows.

Definitive answers

Doherty adds: “We cannot wait for science to provide definitive answers. We must act using the best empirical data we have, which is often muddy but with clear moral compass that points to every effort to make the game as safe as it can be.

“To my mind, a game that has the same rules for youth as for the full professional game has not taken this imperative seriously. It is using the expected scientific confusion to procrastinate over strong action.

“This is why climate change is so difficult. Climate change deniers are saying that there is no proof of man’s effect on the earth. Science will never give such a proof, it can only point and nudge and alert. It’s up to citizens to take a stand.

“Two examples [smoking bans and seat belts] from the history of public health illustrate how, a strong moral vision superseded the science and saved lives.”

It’s medically well recognised that concussion and the symptoms of concussion last for longer periods in children.

A Dublin school currently involved in the Leinster Senior Cup competition have embarked on a before-and-after research project between St James's Clinical Research Centre and Trinity College of their players' brain functions.

Basic aspects

“Elite players at senior cup level have been extremely generous with their time in helping us to understand some basic aspects of the brains reaction to high-level contact sport. We expect to have preliminary results by the autumn.

“I can be persuaded that adults playing either the professional or amateur games – rugby, GAA, soccer, horse riding – can make a decision for themselves,” Doherty continued. “But we have a duty of care to underage players to try to make the game safer not just for head injuries but for bones and joints and ligaments.

“There is plenty of precedent for having separate rules for an amateur sport that is safer. It is also important to note that many amateur boxers make the transition to the professional game easily. I am not asking for a particular rule change, I am not an expert in what is possible that does not change the game into tip rugby.

"In that 1995 game Jonah Lomu appeared to herald a new era of power rugby but in that game I was struck by his instinct to run around the cover into space. I think I would live with rugby as it was in 1995. Could you?"