Olympic gold medallist Sifan Hassan is "curious" about her debut marathon on Sunday in London, a run she describes as a test that is likely to inform how she approaches next year's Paris Olympics.
The 30-year-old Dutch middle-distance runner also admits to a feeling many of the 45 000 amateur runners tackling the London Marathon will sympathise with.
"My feeling is nervous, and curious at the same time," Hassan told Reuters in an interview. "Can I defeat the marathon, or is it going to defeat me?"
After gruelling training runs without food or water during the holy fasting month of Ramadan, Hassan said she has no particular time in mind for finishing the race.
At the Tokyo Olympics in 2021, Hassan dominated the track with a rare triple, winning gold in the 5 000 and 10 000 metres as well as bronze in the 1 500.
If Sunday goes well, she may consider another marathon in the autumn, she said, adding that she still loved track and didn't yet know how her 2024 Paris Olympics plans might change.
In what race organisers say is the greatest ever elite women's field at the London Marathon, Hassan is up against defending champion Yalemzerf Yehualaw, world record holder Brigid Kosgei and Olympic champion Peres Jepchirchir.
Organisers say they see the world record of 2:14:04, set by Kosgei in Chicago in 2019, being broken on Sunday.
"In terms of who's going to win, I do not have a clue," race director Hugh Brasher said. "If that comes down to a sprint finish... I think it's going to be fascinating."
Britain's reigning Commonwealth Games 10 000 metres champion Eilish McColgan was also set to run her debut marathon in the event won by her mother Liz in 1996, but she has been forced to pull out of the race due to a knee injury.
"I've tried, trust me, but it's just got to the point where it's not going to be feasible to run a marathon this weekend," said the 32-year-old McColgan, who had also withdrawn from the race last year due to a medical issue.
"There's been a few factors... A whole host of things in the last three weeks have built up and this knee thing has been the final crack in the armour.
"It's frustrating because I can almost see the start line. I've shed a lot of tears the last couple of days, but there is always going to be another London Marathon."