Age-group rugby players who have been forced to play with older kids due to weight-restriction rules are more likely to quit the sport.

That is the finding of a study conducted by Wellington data firm Dot Loves Data and published in the International Journal of Sport and Health Research. It concludes:
"This study found statistically significant churn rates for children who do not play with their peers," said DLD chief data scientist Paul Bracewell. "Eleven-year-old children who are playing up a grade by weight are 46% more likely to [leave the sport], compared to a player who is in the same team as their peers."

Bracewell says the weight-banding system in junior rugby is flawed and that player enjoyment for those who are slightly heavier than the norm has been disregarded.

Some players are playing at a grade significantly removed from their age group and this causes anguish as 10-year-olds see the world a lot differently from, say, 12-year-olds.


"Their outlooks are different, their expectations are different and their conversations are different," Bracewell said.

His interest in the subject was piqued through personal circumstance. His son, Riley, 11, has a birthday in December and is uncommonly tall. Although he is slightly underweight for his height he still weighed out when registering at his Wellington club. Attempting to make weight, he had to strip to his undies for a second weigh-in.

"It wasn't a great experience for him," Bracewell said. "Last year he was Year 6 playing with Year 8s and it was difficult to make those social connections you expect through sport.

"They go to different schools and they don't have that conversation in the playground about last week's game that leads to excitement about the next match."

Curiosity led Bracewell to Auckland Rugby, who he said were "looking seriously" at the implications of weight restrictions on their playing numbers.

The study used 20,000 observations of Auckland junior rugby players across eight seasons (2009-2016) to determine the likelihood of a player returning the following season and to isolate the drivers of this behaviour.

New Zealand's weight-restricted system has won plaudits around the world, partly because it is seen as fairer and safer. Even Hollywood mega-star Russell Crowe chimed in this year with a column in an Australian newspaper.

"New Zealand… is the torchbearer for ball-in-hand sports in our part of the world," he wrote. "I believe their dominance and consistency is based on the weight system they apply in junior football.

"It keeps the brains in the game longer, lets adrenaline be about competition and not fear."

The findings pose a dilemma for rugby officials. Weight-restricted grades provide assurance to parents that their children wouldn't be overmatched against kids with accelerated physical development.

The fact Pasifika children tend to mature quicker than Pakeha children has been cited as a driver of white flight from rugby in Auckland.

Mt Albert Grammar head of rugby Geoff Moon pointed to the challenges schools face: "In my Year 9 intake, my smallest player is 38kg and my biggest 160kg. They're in the same class," he said. "Those two players require two different pathways."

He was speaking to the Herald in April, when it was revealed that Pasifika players for the first time last year accounted for more than half of Auckland's senior playing stocks, despite only comprising around 15 per cent of the general population.

By contrast, Pakeha numbers had dropped close to 15 per cent in the past five years.

While the proportion of kids affected by weight restrictions remains small, any drop-off in numbers will be keenly felt.

Bracewell said the emphasis on the weight banding should be changed from birth year to school year and that this "pragmatic action" needed to be taken immediately.