Playing Argentina a pain in the neck!

London - Argentina have literally become a pain in the neck for burly All Blacks props Owen and Ben Franks as the length of time scrums are formed has doubled.

When New Zealand play Argentina in their World Cup opener at Wembley Stadium on Sunday a collision of two giant packs is expected.

It's something the Franks brothers relish, as veterans of the dark arts of the front row, but they admit it can take them days to recover.

"If you play a team like Argentina, or South Africa, you have a good three or four days of soreness," Ben Franks said Thursday.

The 120 kilogram (265 lb) Franks has played Argentina three times while younger brother Owen, at 116 kilograms, has packed down against the South Americans seven times.

When the All Blacks played Argentina during the Rugby Championship two months ago, the Argentinian tighthead prop Ramiro Herrara weighed in at 123 kilograms.

With similar sized players around them, when the two packs go down it's 900-plus kilograms of beef on both sides crashing into each other.

Rule changes over recent years have seen the average scrum increase from three seconds at the last World Cup to six seconds now, and Argentina's favourite tactic is to force packs to stay bound and pushing as long as possible.

"The scrum's doubled in length so it does make it a lot harder," Ben Franks said.

"Some teams will try to strike the ball quick to the (number) eight and then push and some teams will leave the ball in the middle then try to push over it. Argentina usually sit the ball there and back themselves to push over."

For Franks that means certain pain for days to come after the final whistle and multiple problems.

"Sometimes driving, turning the neck, you can't turn, reversing, parking. It depends what you're doing, looking after my daughter sometimes.

"You're just generally stiff so you try to move around as much as you can to get the body going but some days it's harder than others."

And it's not lack of fitness for the Franks brothers who are renowned as fanatical trainers.

Owen Franks confirmed a long running rumour in rugby circles that the morning after the All Blacks won the last World Cup the two brothers went to the gym.

"Ben was going down to the gym. I didn't plan on it but we're pretty early risers and I wasn't up to much so I though I might as well go down and lift as well."