One would expect an ultramarathoner who has survived distances of more than 400km to breeze through a 42.195km race.
But do not expect to see Jeri Chua among the first few runners to cross the finish line at the Dec 3 Standard Chartered Singapore Marathon (SCSM).
The 42-year-old admitted: "I'm a slow marathon runner. I don't usually go for speed."
While she will have few problems completing the SCSM for the fourth time, she said that going under 3hr 30min would be a challenge.
"The pace of a marathon is much faster than what I'm normally used to (in ultramarathons)," said Chua, who has done more than 30 ultramarathons and fewer than 10 marathons.
"I don't usually run long distances for my training runs. It's more about getting time on your feet and keeping it as efficient as possible, instead of clocking mileage."
She runs five times a week, a total distance of about 50km. To help her to prepare for the hilly and undulating terrain when she competes in overseas races, she frequently trains at Bukit Timah Hill, where she runs up and down four times in an hour.
PAY HEED TO THE STOP SIGNS
When you've run 400km and then had to stop, it's a really tough decision to make, but you have to deal with it.
JERI CHUA, on why it is important to recognise the physical signs prompting a long-distance runner to drop out of a race.
At this point, some people might think that she is an iron woman. But she pointed out that she faces the same struggles as anyone else.
She has suffered muscle cramps during races, and has been forced to drop out several times - sometimes when she was close to finishing a race.
But she says that is nothing to be ashamed of.
"I don't think I'm crazy, I admit the things I do are a little extreme. But you've just got to take everything in moderation because your body doesn't like extremes.
"I don't ever regret any DNFs (did not finish), less than 10 of them, as long as I have taken away lessons from them.
"When you've run 400km and then had to stop, it's a really tough decision to make, but you have to deal with it," said Chua, who was a physical education primary school teacher almost 20 years ago before a career change.
Running was not her first love. She used to rollerblade and play roller hockey before she began to run seriously. When she studied at Anglo-Chinese Junior College, she would join the cross-country team to train at MacRitchie Reservoir.
Chua recalled: "I didn't hate running but I didn't love it either. I remembered it was hard to keep up with the other cross-country runners, but I had to keep up with them because I didn't want to be lost inside (the trails)."
Although she derives a thrill from testing her mental endurance limits now - she is planning a 24-hour continuous track running event in Singapore - she cautions against pushing too hard.
She said: "A lot of people sign up for races for the wrong reasons or attitudes. A lot of them cannot accept DNFs. They think that just because they've trained so hard for a run, the only way is to complete it.
"But you have to learn to deal with it, if you injure yourself and cause yourself more harm, will it be really worth it to push on?"
She hopes to give fellow runners a boost when she sees them struggling at the SCSM. Chua, who started sports products distributor Woop in 2015, will be carrying an item called CrampFix - a supplement with a sour and sharp taste - which she will dish out to fellow runners who are struggling with cramps.
She said: "Running among a crowd is something I don't enjoy doing all the time. But I'd like to encourage, cheer and clap for people when I run past them. It will be a great addition to the variety of things that I do."