They're used to short, sharp runs on the field, or working on weights at the gym.
Now former Bath Rugby stars are putting themselves to the test in a bike ride covering the length of the country.
David Flatman, Andy Beattie, Danny Grewcock, Lewis Moody and the club's president David Trick are cycling as part of the Deloitte Ride Across Britain event from John O'Groats to Land's End, in order to raise money for the Bath Rugby Foundation.
The charity helps thousands of young people each year through sport, particularly those with disabilities or from disadvantaged backgrounds.
Despite being former athletes, the players are finding it hard to adjust to such a different sport.
Former prop Flatman, now the club's communications director, said: "I thought I'd get some cycling shorts but they don't come in my size.
"And the saddle is pretty tough, people our build are not meant to sit on tiny saddles."
The former players, who all work full time, are finding it hard to fit in the five or six hours a day needed to train.
Flatman, who has already broken one bike, said: "My wife burst out laughing when I told her and said 'There's no chance'. She thinks it's just an excuse for a holiday with the lads."
Despite getting coaching from former Olympic cyclist Rebecca Romero, Grewcocksaid: "I don't think we're going to be ready."
The players got all the essential equipment for their training from Total Fitness in Bath.
They are expected to cycle about 100 miles a day and sleep in a tent each night, starting on June 8.
Along with a group of other foundation supporters, they will cycle nine days in a row without a break, covering the equivalent of Bath to London each day.
Flatman added: "It's important you do it for the right reasons. We know first hand what these guys do at the foundation.
"Those people are endlessly patient and empathetic, they do some amazing stuff. If they can boost the self esteem of a ten-year-old kid then what is more important than that? That is what drives us on."
The ten most generous sponsors will each win two tickets to an exclusive fundraising party with Grewcock, Moody and Flatman. To donate to the Bath Rugby Foundation, visit http://uk.virginmoneygiving.com/team/heavyweights
