While the Kangaroos finished just out of the finals race this year, heavy losses to Collingwood, Geelong, St Kilda and the Bulldogs showed there is a significant gulf between the teams.
But Grima, who had a break-out season in 2010 playing 17 games, believes it's 'staying power' rather than football ability that will help bridge the gap.
"One of our biggest downfalls last year was our aerobic fitness and endurance," he told SEN's Tim Watson, Andy Maher and Andrew Gaze.
"Hopefully when we get back we'll train at a really high intensity and get some more gains there.
"Not so much what we do now will be there in round one, but it's more when we get back we can train at a higher intensity than we ever have before and get the miles in the legs to be able to run it out with the better teams."
The players have been given one full day of rest so far but the respite will be short lived with the snow now falling heavily in Utah and another day of treacherous hikes on the cards.
"When we get up this high and we are hiking around for seven or eight hours at a time, the air is very hard to breathe in.
"Everything you do up here just seems a lot harder than when you are at sea level."
Grima recently signed a new contract with the club and says the decision was made easy due to the club's new high-performance culture under coach Brad Scott.
"I've only been at the footy club now three, going into my fourth year and even the facilities back home make you want to get stuck into your training.
"Coming here, it steps us up another level. We are staying at really nice places and it's just a great opportunity for a young group to come away and experience something we never thought we would."
And the Tasmanian says Andrew Swallow's decision to commit to North for the long term will only further the club's chances of success.
"In the last two years he's really developed into one of our most important players, probably second behind Brent Harvey.
"He's got a big role to play with a young midfield and all the guys respect the way he goes about it. He's a great bloke and I'm not sure what he did get offered to go to Greater Western Sydney, but for him to re-sign at the club means we're rapt. Hopefully guys in the same position will follow suit."
