Plenty has been said and written about modern rugby union but it was England’s oldest living player who offered this week’s most lacerating verdict. “There is no room for finesse any more,” lamented Harry Walker, who made his Test debut in 1947 and celebrated his 100th birthday on Wednesday. “If someone beats one man about three others hit him. They have got no chance. It’s a different game … 11 across the park, I don’t like it.”

The plain-speaking centenarian also gave his considered view on scrums – “Bloody awful. A load of blokes falling down” – with a magisterial certainty that all but scorched a hole through the sports section of the Daily Telegraph. Out of touch? Hardly. In many ways he was simply echoing the growing number of ex-players who worry their sport is turning into American football in front of their (broken) noses. “I look at rugby now and it is just brutal,” says Damian Hopley, the former England centre who is the chief executive of the players’ union, the Rugby Players’ Association. “Part of rugby’s great attraction is its gladiatorial nature … but it is becoming so collision-based.”

En route to Twickenham, the Aviva Stadium or Murrayfield this weekend, you might also ponder the verdict of Dan Cole, an England prop of slightly more recent vintage. He reckons front-rowers, in particular, are destined to grow even bigger and faster, further diminishing the odds for smaller guys looking to elude largely static tight forwards. “The economics of the world market have opened the game up to Polynesians who are naturally that big,” Cole says. “If you’re 100kg and you’re scrummaging against someone who’s 145kg it doesn’t help. But that’s the way the game is going. With front-row substitutions you’re going to get bigger people because you don’t have to do an 80-minute shift.”

Stir in the continuing concussion debate – this week the Rugby Football Union released figures showing reported instances in the Premiership rose by 59% in 2013-14 – and the human breeze blocks now occupying back-line positions once reserved for dancing feet and it becomes ever more obvious rugby is changing. It has altered beyond recognition around the breakdown, in midfield and aerially – to name but three aspects – inside the past decade. Which begs urgent questions: how will the sport look in five or 10 years’ time at current rates of progression? And what are the proactive answers that put players’ welfare uppermost?

Photograph: Guardian

Because if the game continues to worship purely at the altar of size and strength, things are going to get messy. Sure, an excess of muscle can be tempting but so are all harmful addictions. When Jonah Lomu blazed his destructive trail across the 1995 World Cup an All Black fan sent a fax –remember them? – to the team in South Africa. “Remember rugby is a team game,” it read. “All 14 of you pass the ball to Jonah!” It was a joke but no one is laughing now. Our fields are full of Jonahs, making life ever tougher for willowy sprinters such as Jonny May, the slim England winger with dynamite in his boots.

Every summer the brilliant May gazes at the latest crop of Gloucester academy players with creeping horror. “Each year I think: ‘Blimey, these guys are getting bigger, they’re faster, they’re fitter.’ A few years ago some forwards could get away with just being heavy and one‑dimensional. Not any more. Everyone has no option but to push themselves harder. I definitely think careers aren’t going to be as long because of the demands we’re under.”

Which is why Hopley, who had to retire at 27 because of injury himself, reckons the game’s administrators cannot afford to dither.

“Somewhere down the track we’ve got to address some of these issues in the laws of the game,” he stresses, repeating his belief that the season structure and volume of matches also need urgent attention. World Rugby (formerly the IRB) is due to undertake its usual review after this autumn’s Rugby World Cup and a 15-man committee is set to meet in late April to discuss any proposed law amendments. However, as the ex-Lions flanker John Jeffrey and current WR committee chairman, said on Friday, knee-jerk decisions help nobody in the long term. It will be 2018 before Test rugby looks any different, at the earliest.

For the players’ sake, however, something other than their bones and ligaments has to give. Rugby is a contact sport, true, but it is also meant to be a game of evasion. In stark contrast to the marauding rucking of Jeffrey’s era, we are seeing a far more upright, claustrophobic product, a blur of choke-tackles, jackals (turning the ball over after a tackle), guards and blitz defences, all of which have muscled into rugby’s lexicon. Ben Youngs, England’s scrum-half, also points out that enhanced video analysis is ramping up the pressure even more. “It becomes harder because guys are aware of what you are doing. I guarantee this weekend that Sergio Parisse will be coming for me at every ruck. When I am passing left he will be trying to grab me. We have watched about 20 clips of him doing it.”

No wonder old-timers, particularly in France, are increasingly nostalgic for the instinctive days of Serge Blanco. Rugby, at its best, remains a compelling spectacle but the higher the stakes the less space exists. Hence the widespread joy at the displays of Jonathan Joseph and George Ford last week; it felt like a rare victory for specialist craftsmen over hard-running line-breakers. Hopley, though, fears commercial imperatives will delay any reduction in games played and, consequently, the injury toll. “Such things tend to be left behind because it doesn’t suit the bottom line of the unions.

“I actually have a lot of sympathy for World Rugby because they’re governed by the very unions they’re supposed to govern. I look enviously at the commissioners in America who make decisions in the best interests of their sport. Funnily enough, American sport looks pretty successful to me.”

Hopley also makes the point that the amateur and professional games continue to diverge. “There has been a lot talked about the seamless game. It’s an absolute nonsense. They’re two separate sports now and they should be treated as such.”

Either way, introducing weight limits at certain key age-group levels feels like a no-brainer if youthful skulls, joints and enthusiasm are to be better protected.

Sadly, though, the world’s lawyers will chorus “Restraint of trade” if the game ever sought to limit, say, the number of players weighing more than 100kg in a senior match-day squad. As May reminds us, rugby is like the Olympics, where times continually improve: “It’s not good enough to be happy with where you are, we all have to look to get better.”

Which is fine on the track or in the pool but presents a major dilemma on an already crowded pitch. Ditch flankers and permit only 13 players on the field? Reduce the number of tactical substitutions? Doing nothing is no longer an option in the eyes of many. “At what point do the players say: ‘Enough,’” asks Hopley, rhetorically. “It all comes back to leadership. Let’s get the right people in the room, work out what we’re trying to do and do it, with player safety at the heart of everything.”

Perhaps they should invite the redoubtable Harry Walker along.