Rugby: From ballet to cage fighting - how the All Blacks stay ahead

That the All Blacks are constantly searching for ways to improve won't raise a single eyebrow of those with even a cursory knowledge of their record, but some of the team's methods might.

From the Royal New Zealand Ballet to cage fighting in Australia, two worlds which could hardly be further apart, All Blacks forwards coach Mike Cron has seen it all already this year in the name of self improvement ahead of the British and Irish Lions tour which starts next week.

Ballet, he said, can be helpful in terms of the lifting techniques of the dancers, while mixed martial arts, or cage fighting, can give an insight into evading the grapples of opponents.

"Ballet, a lot of it is how they lift and that correlates to lineouts and kick receipts," Cron told Radio Sport's Martin Devlin this morning. "Cage fighting ... was how they get an opponent off them when they're pinned to the ground. There is always correlation with anything you look at if you're pretty open minded about it and a wee bit left-fieldish."

The need for constant self improvement has been head coach Steve Hansen's mantra throughout his All Blacks' reign. His approach is along the lines of "if you're not improving, you're standing still and ready to be overtaken" and that is certainly borne out in Cron's recent investigations.

For Cron, who has re-signed with the All Blacks until the end of 2019, and will retire from his role after that to focus on developing New Zealand's up-and-coming coaches, the endless questioning and a refusal to settle for the status quo is healthy.

"Steve has really driven that too," Cron said. "You can always tap on Steve's door and have a yarn and to be honest he'd be the first guy who, if he made a slight error or mistake or misjudgment or whatever, he'd be the first to put his hand up and I think that's great.

"We're pretty tight knit ... and at the end of the day we're here to make our players better and be the best they possibly can."

Cron, who has been with the All Blacks since 2004 - along with Hansen and managers Darren Shand and Gilbert Enoka - has re-signed with the national team alongside backs coach Ian Foster.

Cron began as scrum coach and took over as forwards coach from Mick Byrne in 2012.

He has experienced plenty along the way, including the development of the players before they even get into the All Black environment.

"Since 2004 to now, the young athletes we get in are far, far better than we had when we started," Cron said. "They're far more professional, obviously because of the different era, but they come in and understand mental skills, the diet side of the sport, how to interact with the media and public, how to do their homework, they're an absolute credit to either their parents, schooling, or [previous] coaches, whatever it may be.

"We've got some outstanding young talent and I can only assume it's the same for netball, hockey, or football and if that's the case it's great for our country.

Like current defence coach Wayne Smith, who will leave his role after this year's Rugby Championship, Cron said he would never coach against the All Blacks. And he won't be persuaded to continue even should the side win their third World Cup in a row in Japan in 2019.

"I think I will have been there for long enough then. It will be time for a younger coach to have a go.

"It's important to give our younger Super Rugby coaches a pathway as well, and I've probably blocked that for long enough."