Rowing heroes Helen Glover and Heather Stanning take on new challenge: London Marathon

COOKHAM, England -- What do you do when you've beaten the world, time and again, when you've got to the point where you seem practically unbeatable and when, with two Olympic gold medals in your glittering collection, you may well be considered the very best sports team in your country?

When Helen Glover and Heather Stanning reached that point in their rowing careers last August after taking their unbeaten record to 39 races over five years and becoming, in Rio de Janeiro, the first British oarswomen to become back-to-back Olympic champions, Stanning, a major in the British Army, decided it was time to retire and concentrate on her military life.

Glover, Stanning's pairs partner, understood. It was the natural time for them to go their separate ways, especially as she was still undecided about her own future in the sport and had just gotten married three weeks after Rio to Steve Backshall, the internationally acclaimed English adventurer, naturalist and TV presenter.

Yet when you've spent every day for years in each other's pockets, locked in joint tunnel-visioned focus on just one Olympic goal, it's not easy to walk away from your once-inseparable athlete-in-arms and best friend just like that.

So the pair who were described, rather splendidly, by one British newspaper after their Rio triumph as the "greatest boating double act since the Owl and the Pussycat" decided on one final sporting challenge. Instead of racing with each other, how about actually competing against each other -- in Britain's greatest race?

Not that they're about to bill their participation in the Virgin Money London Marathon on April 23 as a duel within a race -- Stanning's focus is to raise money for the Royal British Legion Industries army charity, while Glover is running for the Brain and Spine Foundation -- but when you own the sort of cussed competitive streak that has seen this pair win double world and European gold and 10 World Cup races, then you can imagine how much they might want to beat the other.

Asked who was going to win, they both pointed at the other, laughing. Away from her pal, though, Glover was happy to concede with a wry smile: "I always want the best for Heather ... but if I can be a little bit better than her, then great."

It will be every rower for herself out there. Both are suffering from dodgy knees suffered during marathon training. "The training's so much harder on the body than I expected," Stanning mused. "People say, 'Oh, this will be easy for you two,' but we were very good at just one thing -- rowing a boat. Our heart and lungs are great, but our joints aren't used to carrying us. It's much more difficult than I thought."

Yet Glover is the one at the biggest disadvantage. This Saturday and Sunday, she and Backshall will be competing in the 125-mile, nonstop Devizes to Westminster International Canoe Race, one of sport's great endurance challenges. The event can be so brutal -- the competitors also have to haul their kayaks out of the water and carry them on land to negotiate a series of 77 locks -- that even Britain's ultimate Olympian, rower Sir Steve Redgrave, failed to finish it.

This "Canoeists' Everest"/marathon double in the space of seven days, Glover understands, has never been achieved before. Yet, typically, this just drives her on. "She's bonkers," said Stanning, smiling. This prompted a laughing Glover to respond: "At least it gives me an excuse if you beat me in the marathon!"

The pair have a pretty good vision of how the race may unfold. Glover, a talented all-round sportswoman who was once a schoolgirl cross country international for England, is the headstrong one who'll bound off ahead, perhaps too quickly. Stanning is the quiet, calmer one -- at 32 a bit older and wiser than her 30-year-old pal -- who'll go at her own steady pace. "The tortoise to Helen's hare," Stanning described herself.

Glover even admitted that she feared the one point when the two might end up running together could be "at halfway when Heather catches up and I try to hang on to her before she overtakes."

As they giggled about their race, it was easy to be reminded of just why they made such a harmonious team. When they convened to be interviewed at Glover's home in the picturesque Berkshire village of Cookham, they hadn't seen each other for a few weeks but embraced as if it had been a lifetime.

"I miss seeing Helen every day, to be honest," admitted Stanning, who's throwing herself back into full-time military service for the first time since, as an army captain, she ran a team that operated drones to provide surveillance and reconnaissance for the army's HQ in Helmand Province back in 2013, the year after she and Glover had become the first home-country champions of the London Olympics.

The feeling is mutual. "It was an amazing privilege to meet and train every morning with someone who's not just an amazing friend but an amazing athlete and to know you're on this special journey with this special vision together," Glover reflected.

"Every day was really exciting, to be part of a team like that, so not having that is kind of sad, a very, very strange feeling. But it's not a feeling of loss -- more a sense of achievement, of a job well done."

Actually, of a job probably done better than any British rowers before or since. Not only did they not lose a race in the coxless pairs after the world championships in 2011, when remarkably they still won silver even while suffering from the effects of norovirus, but nobody even came remotely close to toppling them, which is why they are still both ranked as the world's top two female rowers.

A hard decision awaits Glover, though. Such a brilliant oarswoman that she won world championship gold with another partner, Polly Swann, when Stanning was on her tour in Afghanistan with the Royal Artillery in 2013, she has been agonising over whether to continue a career in which she has won her past 50 races.

"I honestly don't know what will make my decision for me about whether to carry on," she said. "I keep waiting for this light bulb moment."

For the first time in eight years, she's taking a break to recharge her batteries and enjoy thrill-seeking with her new husband.

"For the last six months, we've been doing all those things together that we'd always talked about -- like scaling up the side of mountains when we were on honeymoon and free diving underwater," she said.

"I love all that. I've always been massively into outdoor sport and adventure. So what a treat to find a full-grown man who likes the same things! Steve's really supportive of whatever I decide. He knows I have to make the right decision for me, and he's saying he's happy if I'm happy."

Time is ticking, though. She conceded that she would probably have to make her decision within the next couple of months because the more training lost, the more her chances of achieving the Olympic hat trick would be reduced.

At the moment, though, she couldn't be happier. Life with Backshall on the stretch of the Thames that supposedly inspired Kenneth Grahame to write "Wind in the Willows" is evidently one big adventure. Their house is like a cross between the Natural History Museum and a boathouse, with a kayaking exercise machine dominating a front room festooned with animal skulls, fossils, a gigantic canvas painting of a lion and the "ethically sourced" puff adder skeleton that Glover bought hubby for Christmas.

His BAFTA for presenting the "Deadly 60," a show in which Backshall has too-close-for-comfort encounters with some of the most dangerous animals on the planet, is nestled next to Glover's Olympic gold medals. You just know there must be executives even now plotting to turn them into TV's first couple of adventure. That DW canoe marathon to raise money to save part of the Borneo rainforest? That could be just the start.

Stanning gazed round her friend's extraordinary home and laughed about how she'd be holding down an army desk job while Glover was gallivanting around the globe. "Maybe I should carry their bags for them," Stanning said.

They're very different characters. Stanning could easily imagine Glover going on to enhance her status as an effervescent Olympic legend. "She'll end up a star -- she's already a star," Stanning said. "Me? I'm quite happy as I am. Just having the quiet life, that's better for me I think."

There won't be anything quiet about army life, but the thoughtful Stanning always seemed less comfortable than Glover in the public glare, anyway.

"Getting back into military life and seeing how I fare will be a big challenge," Stanning said. "As an athlete, I was very selfish about my time, and the Army was really supportive of me, allowing me to go away and be the best I could be at rowing. So now it's time for me to put something back."

As these great athletes prepare for the next chapter, did they ever allow themselves to reflect on their landmark achievements, which were also forged by their coach Robin Williams, who was treated for bladder cancer while guiding them to golden glory?

"The thing I'm most proud of is that if you just happened upon the three of us at any time on a training camp, say on a lake in Italy, and you just happened to see our boat, there'd be no hint of who we are, what we'd done, what our winning streak was," Glover reckoned. "Because we always acted as the underdogs, always as if we had never won a race before. We had a work ethic, a grounded attitude, and kept our dogged determination day in, day out.

"That's why I enjoyed the journey so much, because we had that fire, that absolute desire to win, as if we'd never won anything before. And it's in those quiet moments when there were just the three of us around, away from the podium and the lights and the crowds, that I think I'll always be most proud of because that's where our medals were won. We really did make a great team."

They still do. One day, they reckoned, we will see them back where they belong -- in a boat together. "Whether it's competitive or not," said Glover, smiling and glancing at her best friend, "we'll still find adventures, we'll still find challenges together."