It's perhaps the most striking image from the 2018 Commonwealth Games. Leading by two minutes in the marathon event, Great Britain's Callum Hawkins began stumbling across the road, falling and rising once before eventually collapsing into a railing.
The weather on Australia's Gold Coast was sweltering that day and Hawkins – used to the colder conditions of his home in Scotland – succumbed to heat exhaustion. As he was driven away in an ambulance, a dream that had been a year in the making was over.
"It was a bit of circumstances and my own fault, a mixture of tiny little things that all added up to a big problem for me. I don't remember too much after I fell over the first time but I've learnt a lot."
"It still annoys me to think about it because it feels like an opportunity missed. But it is a big learning curve for what Tokyo could possibly be – or Sapporo [the venue of the Tokyo 2020 marathon] because it can still be quite hot there."
But as many Olympians know, it's not about how hard you fall but about how high you rise.
A year later at the World Championships, Hawkins was back racing in the intimidating heat of Doha. Against a world-class field, Great Britain's brightest marathon star finished a hugely impressive fourth.
Now with Tokyo 2020 less than six months away, Hawkins is looking to go one better and bring home a medal in one of the most highly-anticipated events on the Olympic calendar.
"I'll definitely go for a medal," he said. "I'll put myself out there, but it's going to be tough. I know I finished fourth at world champs but there'll be a lot more of the big guns going to the Olympics and it'll be a lot stronger field."
Born to run
Sometimes in life, you just don't have a choice.
For Hawkins, whose dad was a national-level runner, and whose two brothers were also among the most talented runners in the country, being anything other than a runner would have raised eyebrows. Even his mum, who had no history in the sport, took up running to keep herself fit.
"Between myself, my dad and my two brothers we have 12 Scottish cross country titles between us all," said Hawkins. "And my dad, my brother Derek and myself all have the Scottish under-15 cross country trophy as well.
"My dad was my coach since I was nine years old, so it was always running talk over the dinner table. My mum got quite sick of it at times!"
Nowadays, only two of the three brothers run, but both Callum and his brother Derek raced at Rio 2016, and Derek still has a chance to qualify for Tokyo 2020 – provided the opportunities present themselves in time.
"It really depends how the lockdown and races go, because at the moment you can't predict if races are going to be on or not," explained Hawkins. "So he's throwing everything he can into the trial [Great Britain Olympic marathon trial], which should be at the end of March and hopefully he can do it."
The Hawkins brothers live together, train together and are coached together. But it's not often that the two get the chance to race together, other than one particularly tight sprint finish that Callum seems to remember as if it were yesterday.
"[There was] a race in Ireland where we had a sprint finish with each other. He won," Callum, the younger of the two brothers recalled. "I was catching him and I just didn't have enough. There wasn't enough racing left... I kind of mistimed it but he just edged it."
Grinding through the gears
The marathon race has always held a unique air of mystique. Even the very origins of the race – where the story goes that an ancient Greek messenger ran 25 miles from Marathon to Athens to spread word of a Greek victory, only to collapse and die upon arrival – are steeped in legend.
This year's event has no little magic tied to it, with sporting greats including Kenya's Eliud Kipchoge and Ethiopia's Kenenisa Bekele expected to lead an all-star field in one of the Olympic blue ribbon events.
But Hawkins, who has proved his ability to rise to the challenge of championship events, will not be daunted when he takes his place on the starting line in Sapporo.
I could easily get a medal but I could easily finish outside the top 10
Hawkins has always been something of a 'big-game player'. His best results cannot be measured in terms of time, but rather in his ability to rise to the occasion and maximise his performance under the bright lights.
During the world championships in London (2017) and Doha (2019), he achieved two fourth-placed finishes against athletes who were arguably expected to beat him. And there will be more to the Olympic marathon than the records you bring to the starting line.
"I'm probably more suited to a championship race than a straight-up time trial when you compare it to the world's best. I think – apart from the Gold Coast – I am pretty good at reading my own body and how to get the best out of myself and for some reason championship races are anyone's game."
Even so, Hawkins is aware that while a medal is in his sights, finishing far lower down the pecking order is also a possibility. And with the competition being so strong, neither could be seen as a failure.
"I could easily get a medal but I could easily finish outside the top 10," he said matter-of-factly. "For championship marathons, it's a bit of a gamble, anyone can do it!"
Sweating it out
In 2020, the Olympic marathon venue was moved from the city of Tokyo to Sapporo due to the expected hot and humid weather conditions so often seen in Japan's capital during July and August.
But that doesn't mean Sapporo will be anything close to the conditions Hawkins is used to in his native Scotland. Average highs in July are still 25 degrees celsius – gruellingly hot for marathon runners taking on a 42km run.
But having experienced the extremes of heat exhaustion at the 2018 Commonwealth Games, Hawkins redeemed himself in the heat of the 2019 World Championships in Doha, where temperatures soared to up to 32 degrees celsius.
And when it comes to Tokyo 2020, the GB athlete is going to do everything he possibly can to be ready. Even recreating the sweltering conditions in his garage – something he already experienced during the build-up to Doha.
"It's quite difficult to be able to get a heat chamber hired, because there are not many in Scotland. So I said, 'I'm pretty sure I can replicate something similar in my garage'."
"So I did two weeks training in Majorca to get my heat acclimatisation and then just to hold on to it for the Doha world champs, I just got a treadmill in my shed and put some heaters in!"
42.195km to glory
For a race that is so long, the difference between winning and losing a marathon often comes down to small margins.
Eliud Kipchoge's official world record of 2 hours 1 minute and 39 is only two seconds faster than Kenenisa Bekele's best time.
And if anyone needed proof that upsets can happen, October 2020's London Marathon was a prime example that you should expect the unexpected. In an event coined the 'race of the century', odds-on favourite Kipchoge finished eighth, while second favourite Bekele suffered an injury that meant he didn't even make it to the starting line.
Hawkins, whose late surge in the 2019 World Championships saw him leading the race with close to a mile remaining before eventually falling to fourth, knows a thing or two about the fine lines that define victory.
"Doha, I was really disappointed to finish fourth because I'd already done it [in London]. I went out for a medal and to be only six seconds off, and also come into the front group on the last kilometre, it was pretty disappointing for me."
"But that's the breaks. That's running."
But with the disappointments of near misses firmly in the rear view mirror, Scotland's Athlete of the Year can look forward to Tokyo 2020 with the hope that the marginal gains he has been working on in training will bring him closer to an elusive medal.
And when the heat is on at the world's greatest sporting event, his experiences of both wilting and shining under the bright lights will both be equally important as he strives for Olympic glory.