(CNN) In the past year, Briton Jonny Brownlee has grown accustomed to people jokingly asking if he needs help crossing the road.
Despite boasting 23 global senior medals at Olympic, World and European level with older brother Alistair, the Brownlee siblings, who are triathlon specialists, admit their world renown is as much for the one that dramatically got away.
Leading the World Trialthon Series finale in Mexico, Jonny was 700 meters away from the win that would have given him global glory only for his body to dramatically start shutting down.
Battling for second with South African Henri Schoeman, Alistair scooped up his brother, carrying him to the finish, thrusting him over the line in front of him, a noble gesture even if it proved insufficient for that World Series title.
"Occasionally, people shout to ask if I need help crossing the road," Jonny tells CNN from a pre-Christmas training camp in Spain as he recalls the moment in September 2016 when the image of brothers in arms went viral. His response, he says, is to smile and move on.
Even in a local supermarket in Alicante where he is currently spending 10 days on a training camp, Jonny is now being recognized more readily than he has been at anytime in his career.
"People stop and say how nice he [Alistair] was," he says. "It's actually all people ever say."
No day off on Christmas Day
To their credit, the siblings have embraced the incident, one that has brought the once bickering brothers closer together.
Growing up, even playing a game of Monopoly could spark an argument between the brothers. There is also a third Brownlee brother, Edward, who is younger than Alistair and Jonny.
Spending this Christmas at their parents' Yorkshire home in northern England, the two triathletes will happily join in the board games but with a surprising lack of desire to win.
"I think we used up all our competitiveness for stuff like that as children, and we get enough competition from the day job," says Alistair. "There will be other people being competitive in the family."
While they will allow their svelte frames the luxury of gorging on the festive offerings, Christmas Day won't pass without a training session.
"It's never a case that I'm worrying about what my rivals are doing on Christmas Day, it's more a case that I'm used to exercising," adds Alistair.
Sporting siblings spur each other to success
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So the triathlete brothers will hit the roads for an hour-long run, their minds on the collective first goal of next season -- Commonwealth Games gold on Australia's Gold Coast in April. The brothers will represent England at the Games.
To date, Alistair has predominantly taken the bragging rights, winning the last two Olympic titles as Jonny finished third and second in 2012 and 2016 respectively.
For Jonny, the result in 2012 was easy to bear, less so last summer in Brazil, where he admits the idea of damning his brother crossed his mind.
"I was in such good shape in Rio," he says. "I was training so well and running faster than him so that sort of irritation crossed my mind briefly but, if I hadn't won, I wanted it to be him."
So will 2018 be the year when youth finally gets the better of experience?
"Well, I hope so but I thought the same thing in 2016 and look what happened then!" adds Jonny with a laugh.
World's toughest endurance challenges
The spectacular setting of the Himalayas is the battleground for the Yak Attack -- a 400km feat of mountain biking endurance and nerve. IInvolving 12,000m of climbing over the highest mountain pass in the world, competitors have to cope with the effects of altitude, frostbite and snow blindness.
The Four Deserts ultramarathon race series challenges competitors to take part in races in the Gobi Desert, the Sahara, the Atacama and Antartica. Each race covers 250km over seven days in some of the world's most inhospitable climates. Athletes carry their own food and equipment with only limited assistance.
Paragliding experience and a heap of endurance are the requirements if you take part in the Red Bull X-Alps - a biennial event which requires competitors to traverse the length of the European Alps -- nearly 900km -- from Salzburg in Austria to the Principality of Monaco. The route goes from mountain top to mountain top but you must also trek with all your equipment.
The EWR South Pole Race tests competitors to the limit as they brave bitter temperatures of -40C and blinding snowstorms in their trek across the infamous Antarctic Polar Plateau in the footsteps of great explorers such as British Captain Robert Scott and the Norwegian Captain Roald Amundsen.
An ultra distance race of 100 miles (160km) is tough enough but the Western States 100 has athletes battling high altitude in the Squaw Valley at 1900m and and over 5500m of climbing -- all in under 30 hours.
The Norseman in Norway is surely among the toughest of all ironman events with the start seeing athletes jump into a freezing fjord to swim 3.8km. They cycle 180km through mountainous terrain and the 42km marathon run finishes on top of the 1880m Gaustatoppen mountain.
Competitors in Earth in the Jungle Marathon tackle 220km of inhospitable terrain in seven days, battling swamps, poisonous trees and intense heat in the Amazon. Athletes are self-supported to toughen the challenge.
Patagonia is a forbidding but spectacular setting for an endurance adventure race. The teams of four in the Patagonia Expendition Race must tackle 600km -- using foot, bike and kayak over multiple days in the territory straddling Argentina and Chile.
The concept is simple. Cycle 4828km across the United States, either in teams or alone. No less than 51,800m of climbing are involved as you cross 12 states from California to Maryland. The cut off time is just 12 days which means sleep deprivation and exhaustion are major issues, not to mention the changing weather conditions.
The Hawaii Ironman is the most famous event in triathlon but also among its toughest. Intense heat and crosswinds bring competitors to their knees as they tackle the 3.8km swim, 180km bike ride and marathon run on Kona Island.
The Dead Sea ultra marathon is a 48.7km run with a difference as competitors go from a starting point over 900m above sea level in Amman to finish at the Dead Sea at 400m below sea level. Heat is a major inhibiting factor in this endurance test.
The Swedish archipelago is the setting for the Otillo, which sees teams of two swim 10km and run 54km over the course of 14 hours. The cold water is continually entered and exited and many choose to swim in their shoes, even wearing a rucksack, and run in wetsuits.
The Cape Epic in South Africa is one of the most famous mountain bike races in the world with teams of two competing over 966km of terrain over six stages with massive climbs and daunting terrain.
Alpine climbing is the order of the day in the La Haute Route which starts in Geneva and finishes in Nice. Competitors can expect to ride around 730km over seven stages, with up to 17,000m of ascent. Many of the classic cols of the Tour de France are tackled on the way.
The start of the annual Comrades Marathon -- a famous ultra distance running race -- which sees over 12,000 runners tackle the 89.2km from Durban to Pietermaritzburg in South Africa.
The Kona dream
As Christmas approaches, the good news for Jonny is that he would appear to be in the ascendancy. Alistair is four-and-a-half months into his rehabilitation from hip surgery while Jonny, bar the odd niggle, has come through winter training relatively unscathed.
Climbing high in spain #cycling #mountainlife #ValDeEbo
Alistair is no stranger to injuries, which previously have curtailed his training only for him to peak at the right time.
"It's not ideal and I'd like to have done more before the Commonwealth Games but I've come back from injury before like this and having done something like that before makes it easier," says Alistair.
But he is well aware of the threat his little brother presents: "I'm sure he'll beat me one day."
As for Jonny, his aims are clear: "I want to be Commonwealth Games champion and then Olympic champion in 2020."
Whether Alistair will still be racing at the same distance come the Tokyo Games is uncertain, though the lure of a third Olympic title plus the mixed team triathlon elay being added to the Games schedule mean he will most likely compete in Tokyo and put his Ironman ambitions temporarily on hold.
The dream for both after the 2020 Olympics is to win Kona, the Ironman World Championships in Hawaii.
READ: Blind triathlete's Kona dream
"I grew up watching Kona, that really was the pure side of the sport," says Jonny. "It's not necessarily the pinnacle of the sport, being British that's probably the Olympics."
Despite the brutal temperatures in Kona and the eight or nine hours swimming, cycling and running that's involved, Jonny simply wants to try it to see how he and his body fare under the torment.
"Kona is definitely something that's a big aim for me and it's hard to say if winning that would be bigger than Olympic gold as I've not done it," adds Alistair.
For all that Alistair has won, he insists he has never lacked for motivation, his goals ever shifting, a change of equipment in terms of their bike suppliers for the season in Scott, giving him renewed impetus.
"Psychologically, getting something new like that is always a boost," says Alistair.
Iron men and women
A 3.8 kilometer open-water swim, followed by a grueling 180 kilometer bike ride, rounded off with a lung-busting marathon. Are you ready to push the limits of human endurance? (All pictures shot by Charlie Crowhurst; courtesy of Getty Images)
Over the last year British photographer Charlie Crowhurst has covered a number of triathlon events in Europe, producing otherworldly images which highlight the exhausting, lonely reality of endurance sport.
This photograph by Crowhurst almost has a volcanic feel about it, setting the swimmer against the backdrop of the fiery red sun setting in the distance.
Each triathlete is given a number before undertaking the challenge. "I guess people do it to give themselves a goal or something to aim for," Crowhurst told CNN. "Perhaps they can't achieve anymore in a working capacity and want to push themselves in another field."
Crowhurst uses digital filters to create his own unmistakable style. "These events are a real test of not only physical stamina but mental too and I think a lot of people underestimate the mental aspect and how tough that can me," he said.
One last deep breath before this competitor prepares to take on chilling waters at the Challenge Almere event in the Netherlands.
Here, a conventional shot of one of the competitors is shown. "I usually look for about a dozen pictures using a digital filter but it's interesting to see the contrast," said Crowhurst. The effect is striking...
Crowhurst's use of filters creates a much more dramatic portrait of the competitor."Essentially it's human versus clock and you're pushing you body to its limits and, for some, training for it can dominate your life," he explained.
Triathlons can become a battle between man and nature. "The winds hitting the competitors on the bike leg of the Challenge Almere event this year were particularly strong," said Crowhurst.
"I don't have a favorite picture. You always enjoy the work you have just done," said Crowhurst, who captured thick cloud lingering over the start line of the Challenge Austria event in Walchsee.
Crowhurst uses different forms of transport to shoot the competitors, meaning he doesn't have to complete a triathlon himself. "The best shots on the swim leg come if you are able to get in close on a boat," he revealed.
The transition between the different disciplines is key to ensuring competitors secure a good time. "Personally I feel quite emotional when I'm standing at the finish line watching some of the participants finish, as you can feel and physically see how overwhelmed with emotion they are at what they have just achieved," said Crowhurst.
Crowhurst is the son of photographer Alan Crowhurst, who has used similar digital techniques to cover horse racing and sailing events.
"I really liked this shot of a single cyclist set against the windmills," said Crowhurst, of this dark image taken at the Challenge Almere event in the Netherlands.
Crowhurst captures the loneliness of a long distance cyclist during an Ironman event.
Reigning world triathlon champion Javier Gomez is pictured on his way to winning the Challenge Barcelona race in 2013. '"An amazing athlete," said Crowhurst.
Spain's Gomez came out on top after an energy-sapping four hours of racing.
Long into the night the final finishers cross the line at the Kalmar Ironman in Sweden, many hours behind the winners. "When you see them coming in after 15 hours or more I feel it almost adds to the sense of emotion and real achievement," says Crowhurst.
That winning feeling. Henrik Hyldelund of Denmark crosses the line first in his home Ironman in Copenhagen earlier this year.
Crowhurst usually concentrates on capturing the efforts of the non-elite competitors and uses a motorbike to find the best spots on the course to capture their plight, perfectly illustrated at the run leg of the Challenge Austria event.
The lesser athletes can, as Crowhurst explains, produce the most touching stories. "I remember I came across one guy in Copenhagen who was balling his eyes out," he recalled. "I asked him if he was OK, and his reply was, 'Yes I'm fine, I just beat my time last year by 30 minutes.'"
A competitor in Sweden feels the pain after completing the 226km endurance test. "My respect for anyone finishing these events is total," said Crowhurst. "Personally I feel quite emotional when I'm standing at the finish line watching some of the participants finish, as you can feel and physically see how overwhelmed with emotion they are at what they have just achieved." (All pictures shot by Charlie Crowhurst; courtesy of Getty Images)
'Train with the best'
Whether on two wheels, on the water, or on two feet, as ever the goal is for a Brownlee one-two at the Commonwealth Games in a few months' time.
For Jonny, was there ever a sense he might split from his brother and try his own path in a different training group?
"I think athletes as a whole tend to be quite scared of change," he says. "I've never really thought about it. It's always good to train with the best and Alistair's proved he's that.
"I've been afraid of change in the past but my training now differs to his in that I might go shorter or harder or easier on any given day. We'll see if that pays off."
Medals aside, the one joint aim is for the race in Australia not to end with one helping the other across the line. As Alistair concludes, "I think we've done that one!"