Banchory’s Great Britain international Robbie Simpson makes his ultra-distance race debut in California this weekend.
The 2018 Commonwealth Games marathon bronze medallist has never previously competed in an event lasting much more than three hours.
He can expect to be on his feet for up to six hours or longer on Sunday.
He is competing in the North Face Endurance Challenge, a 50-mile race held along the trails of Marin County to the north of San Francisco.
Simpson had planned to tackle his first ultra-race in France last month but a ferocious electrical storm forced organisers to cancel the event.
The wild fires which recently swept parts of California threatened this weekend’s race but fortunately there is no longer any danger of cancellation.
Simpson said: “I am excited to be going to the US to compete for the first time.
“I had actually thought about doing this race before the one in France came up, as it was recommended to me.
“It’s a famous race and some runners I know over there say it should suit me.
“It has some good, fast trails and the weather should be fine, not too hot.
“There’s about 10,000ft of climbing over the route, but there’s no single big climb.
“It’s all spread over about seven or eight relatively smaller climbs so that should suit me at the moment.
“There’s nothing too steep and there’s a lot of fast running.”
Simpson has enjoyed success in road and mountain marathons, although he is taking a step into the unknown by tackling such a long event.
It is, however, a challenge he is relishing.
He said: “It will certainly be different.
“It starts at 5am so we will be running in the dark for the first couple of hours.
“But that should be fine as the smoothest and widest trails come at the beginning of the race.
“It starts at Mill Valley and follows quite a complicated route over towards the coast and back again.
“We finish by running across the Golden Gate Bridge into San Francisco so I am really looking forward to that.
“It has been won in under six hours in the past but I believe the course has been changed.
“I’m planning to be out for six hours or a little longer but it’s difficult to know how it will go.
“I need to run it sensibly as there’s no point in setting off too hard. I need to run comfortably for as long as possible.
“The toughest climb comes around 25 miles so I’d like to get that out of the way before beginning to push on. I need to keep going even if there are people well ahead of me because anything can happen in such a long race.”
Simpson can expect some serious competition from a number of experienced and hardened ultra runners.
He said: “There are a couple of thousand people taking part, including some very good Americans.
“There’s a guy called Matt Daniels who has run a sub-four minute mile and under 29mins for 10K but he’s also an outstanding ultra runner.
“Zak Miller, who has won the Western States 100-mile endurance race a few times, may be competing.”
Simpson’s future ultra-distance ambitions will depend to some extent on the outcome of the Californian race, but he is keen to test himself in the years ahead.
He said: “I might try another one later next year but I don’t want to do too many at this stage in my career.
“The Comrades race in South Africa appeals but I might look at that in a couple of years.”