NZPA 09.Jun.2010Getty Images
"I stay well away from that. I don't know how much, but I saw a fair amount of weight on the squat bar yesterday. It's way out of my league, I feel quite embarrassed," their captain Richie McCaw said.
The Crusaders props, named today to become the first All Blacks test brothers-in-arms since Robin and Zinzan Brooke in 1997, are officially the strongest members of the 26-man squad.
All Blacks scrum guru Mike Cron, who spotted each playing during their school days in Christchurch, marvels at their efforts with the heavy iron.
"I was told yesterday they were doing about a 240kg squat, 500 pounds in the old language. It's just on the day who beats the other. It's great competition, I love coaching them," Cron told NZPA.
"You get some very strong people in the gym but they don't necessarily transfer that into functional strength out on the paddock, whereas these two do."
The pair were born almost four years apart - 26-year-old Ben in Melbourne and 22-year-old Owen in Motueka - but have nearly identical dimensions. On their official All Blacks stats, each are listed at 112kg, with Owen 2cm taller at 185cm.
Owen has nine tests to his name and Ben a solitary All Blacks match against Munster in Limerick in 2008.
Their form amid a powerful Crusaders scrum this year saw them both summoned ahead of incumbents Tony Woodcock and Neemia Tialata to clunk heads with Irish props John Hayes and Cian Healy.
It was a proud moment for Cron who feels the All Blacks' propping depth is healthy.
"No one works harder than these two boys, they leave no stone unturned with their diet or their training or their preparation, and they're All Blacks because of it."
Ben Franks, like Tialata, can play both sides of the scrum which Cron sees as invaluable. The elder Franks will play loosehead on Saturday with Owen in his specialist tighthead spot.
With all the hand-wringing over Carl Hayman's decision to turn down a New Zealand Rugby Union (NZRU) contract in favour of rich French club Toulon, Cron sees Owen Franks as one of the key All Blacks with just over a year until the World Cup.
"You just don't get tightheads at his age. Tighthead is the hardest position on the field to play, physically. You never have an easy day, just some harder than others. Last year he was 21, fronting against South Africa then the end-of-year tour.
"This year he's come back better, he's matured a heck of a lot from being in the environment, he's comfortable here and he's a lot better at the cleanout.
"He's a very physical man and sometimes the physicality got ahead of the brain. The Crusaders helped him sort that out and he's a bright, young intelligent footballer."
Cron just hopes English referee Wayne Barnes controls the scrums fairly on Saturday, and predicts the Franks boys will help keep the All Blacks steady in the crucial facet.
"Through their powerlifting they stay strong with movement and that helps them get out of difficult situations and stay strong. They're quite flexible which is a must for a prop now. They're going well and we'll see how they go on Saturday night."