Sunday was supposed to be the culmination of more than a million training miles and the collection of many millions more for good causes around the country and world.
For some, despite the London Marathon’s postponement until October, it still will be.
The 2.6 Challenge, which aims to raise money for charity during the lockdown, begins on Sunday with people all around the country dreaming up creative activities to inspire donations and sponsorship. Here are some of the stories so far…
The virtual dozen
Eleanor Davis was supposed to be on the startline of the elite race in South-East London on Sunday.
She will still be pulling on her trainers, but instead it will be to run into one of Stockport’s covid wards where she works as a doctor.
She is part of a 12-strong team of some of Britain’s top women’s marathon runners who will each run 2.6 miles as part of a relay.
Also involved are Jess Piasecki, the fastest British woman in 2019, Jo Pavey, a World and European medallist and Hayley Carruthers, who crawled over the line to a new personal best and viral fame in the 2019 race.
Davis usually works part-time so that she can combine her medical career with her sporting one, but has been working extra shifts since the coronavirus pandemic extended to the UK. Although she has been covering longer distances at a slower pace over the past few weeks, the incentive of another virtual challenge inspired her to a new 5km personal best last week.
She and her team-mates will be raising funds for mental health charity Mind.
On the men’s side Dewi Griffiths, who missed last year's World Championships through illness, will be aiming to do two laps of his regular 5.5 mile training loop, clocking under 26 minutes for each. He will be raising money for Air Ambulance Wales.
The six-time winner
Baroness Grey-Thompson won the London Marathon wheelchair race six times, in addition to 16 Paralympic medals, during her career.
This will be the first time that she has not spent a spring day in the capital in 30 years of competing and commentating at the London Marathon.
She will be doing 10.3km - "a marathon is a bit beyond me these days!' - on the roads near to her house as she shares the full marathon distance with two colleagues from ukactive, a non-profit organisation promoting fitness for all that she chairs, who are raising money for the Trussell Trust, which supports food banks.
Her kit will be different to that used during her racing days.
"I don't think I can vaguely fit my bottom in that anymore!" she told BBC Sport when asked if she would be dusting off her old race chair.
"It was built for me when I weighed 45kgs and the diameter across the top was only nine inches. So I will be doing it in my day chair, which is fine. Ish!
"I still do lots of physical activity, just not in that race chair. My old wizened shoulders mean I use a hand bike, go to the gym and do lots of stretchy band work."
She and her colleagues are completing a total of five backyard marathons between them.
The ultra-distance athlete
For some, even the 26.2 is not enough.
Kate Jayden, a 33-year-old compliance officer and endurance athlete, was supposed to be doing the London Marathon as her first race of 2020.
The race’s postponement has meant she has ended up doing more rather than less however.
As you read this, her challenge has already begun with a 26.2-hour indoor cycle ride in her living room. She will climb off the bike at 02:20 BST on Sunday morning, before moving just a few yards to climb aboard a treadmill and begin a 26.2-mile run at 09:00 BST.
“I’m known for doing crazy challenges but this one is a little crazy even by my standards,” said Jayden.
“The mental strength for this will be the real test on a treadmill and in the same place in the same room for so long.”
She will have some virtual company for the running leg of her challenge with friend Jenna Maudlin, in lockdown several hundred miles north in Scotland, completing 26.2 miles via more than 2,000 laps of a 20-metre course around the car park at her block of flats.
She will be doing each mile in a different way, for example dressed as a dinosaur, side-stepping or galloping like a horse, after suggestions from her friends and sponsors.
Maudlin, who has previously cycled from Lands End to John O’Groats and ran 17 marathons in 2017, hopes her variety of styles can compensate for the monotony of the course.
“One of the things I loved about those previous events, was seeing new things and new places and it helped with motivation, so running over 2,000 times round a car park is mentally going to be very tough!” she told BBC Sport.
Jayden is raising money for Trussell Trust and Mind, while Maudlin is running for Age UK, Mind and Save the Children.
Dr Adam Revill fell ill with coronavirus on 29 March. A consultant in the intensive care unit at Torbay Hospital, it would have wrecked his plans to run under three hours at the Manchester Marathon had the race not been postponed because of the outbreak.
Thankfully his symptoms were relatively mild and he is back on the wards and back in his kit for a back-garden marathon, taking on his sister who is doing the same in her own garden in the Midlands.
"I think those 260 laps are going to be the hardest thing I have done," he told BBC Sport. "Lots of turning corners, lots of ups and downs. I am aiming for four hours if we can. And to beat my sister if I can!
"It won't be the slowest marathon I have done though. I ran the Medoc Marathon in Bordeaux where the chateaus open up and crack open the good stuff for you. There is a six-and-a-half hour limit and we pushed it to the limit!"
Cheered on by daughters Ava and Matilda, he is raising money for the Rowcroft Hospice.
"It costs about £8m to run their hospice, 75% of which comes from the community," he said. "But because of the lockdown they are not raising any money from the shops or events like the London Marathon. It is an excellent cause."
The cartoon character
David Smith is a veteran of the back-garden marathons. He has already completed ‘Brighton’ and ‘Manchester’ this month in his garden in Chesterfield – a total of just over 500 laps on each occasion, punctuated by a break for bacon sandwiches from the kitchen halfway through.
On each occasion he brings some local flavour to the course by recreating local landmarks and his well-worn Scooby Doo fancy dress.
“We have a bicycle wheel for the London Eye and a wheelie bin representing Canary Wharf,” he told BBC Sport.
“Scooby Doo is the same age of me – 50 years old – and is still on TV today. Everyone recognises and connects with him. I have about three different Scooby Doo outfits – a warmer one for winter, a lightweight one for spring and then a summer one.”
Before lockdown came into force, Smith claimed several marathon world records to his name, including the fastest controlling a tennis ball (four hours 13 minutes) and the fastest wearing bike leathers (four hours), set in the heat of the London race of 2018.
All his efforts are to raise money for Sands, the stillborn and neonatal death charity.
When not running, Smith works as a pharmacist, seeing first hand the stress and strain that coronavirus has brought to some of the most vulnerable in society.
“We have been extremely busy. There are a lot of people out there who are quite frightened, not only dispensing prescription, but advising people and delivering medication to the vulnerable. I have been very proud of my team, who have been coming in and working extra hours to help.”
The 2.6 Challenge is being supported by a host of stars from stage, screen and sport including singer Ellie Goulding, actor Stephen Fry, Rugby World Cup winner Jonny Wilkinson, Wales and Real Madrid footballer Gareth Bale, British tennis number one Johanna Konta, Tour de France winner Chris Froome and a team of 26 Olympians creating a 26-minute workout video with a succession of 60-second cameos.
Join the BBC's coverage
The BBC Sport website will run a live text commentary page from 10:00 BST on Sunday to feature the best of the 2.6 Challenge's opening day, and would love to feature your activity. Send us a picture and tell us why you're doing it to #bbcathletics on Twitter.