Helen Glover and Heather Stanning like to sweat for their impressive medal collection - but their latest effort even pushed them close to breaking point.
The double Olympic rowing pairs champions went from team-mates to friendly rivals as they started the Virgin Money London Marathon and then pulled on their trainers to tackle the 26 miles 385 yard course with 40,000 others.
Glover admitted she 'hurt all over' after crossing the line in three hours, five minutes and 25 seconds - good enough for a stunning 114th place - while Stanning came home just under 27 minutes later.
"That was probably the best win of my life," joked Glover, as Stanning stood alongside her.
"That was amazing fun but it really, really hurt. The crowd support was remarkable and to have an experience like that for our very first marathon is pretty special.
"However, I definitely prefer it when we do things together, even though we had all that support out there you are totally on your own when you are running and only you can motivate yourself.
"Two things got me in front of the TV when I was a kid and that was the Olympics and the London Marathon and this has been such a special experience, especially sharing it with Heather."
But Stanning - ever the ferocious competitor - is already smarting for revenge and eyeing the sporting calendar for their next challenge.
"I need to choose another sport to take her on at to give myself a chance but we've both really enjoyed the different challenge," she said.
"We competed in front of a home crowd at London 2012 but this was amazing too, it was exactly what I wished for. The crowd were shouting my name and spurring me on, they really dug deep for me and they got me through that last ten miles."
Glover is yet to decide on whether to have a crack at a third Olympics in Tokyo while Stanning announced her retirement last November to focus on her army career.
It marked the end of one of the most successful British sporting partnerships in history, with the duo not losing a single race together between the 2011 World Championships and last year's Olympics in Rio.
"I'm really not decided on the future, it's just been nice to train for something without feeling all that pressure on your shoulders," added Glover.
"I’ve been pushing myself for ten years to be the best in the world but I honestly don't know about the future because I've not really been thinking about it."
Meanwhile, fellow rower and two-time Olympic champion James Cracknell came home in an impressive two hours 43 minutes and 12 seconds to finish just a couple of minutes ahead of Chris Newton, a three-time Olympic track cycling medallist.