A race with no finish line might be considered a nightmare to some.

For many this weekend it's a challenge right down to the last one standing. 

The Outrun Backyard Ultra will be winding its way through the Sheep River Valley this weekend with over 50 racers side by side, bringing amateurs beside seasoned vets of the sport.

The rules are simple: once the race starts, runners have one hour to complete a 6.71-kilometre course. Once finished they can use the remainder of that hour to stretch, eat and rest. Once that hour is up, they do it again, and again until they can't finish the course or run out of time. This format can keep runners going for multiple hours, even days.

Taking part this year is Britt Ivan a local ultra-marathon runner who is no stranger to long-distance treks. Her first Backyard Ultra took place a few years ago.

"The year that I was going to do a marathon was 2020 and of course, everything was cancelled. My coach at the time, Dave Proctor, who just ran across Canada, said, ‘I have a good idea. Let's do a quarantine backyard ultra.’ It all happened over ZOOM. That year I was only going to do a marathon and I thought, ‘well, this is fine, why quit there.’

"So I did 100K."

However, this race brings something she isn't used to: other runners.

"I did another one a couple of months later and that one was outside. I was still by myself though. I just did my own loop. In this one, I get to run with other people. So that's exciting."

They aren't allowed breaks or headphones while running resulting in this challenge becoming a mental game as much as a physical one. 

"You have to think of like fueling and hydration. For the people who are going to be in there for the long haul, can you get any sleep in? Because it's not like it quits at any point. It just keeps going and going and going. Nobody takes a break. There's no, ‘alright, let's come back tomorrow.' "

What makes it especially difficult is the absence of a set finish. 

"Your brain really wants a finish line. ‘How much longer do we have to put up with this nonsense?’ And if you can give it an answer like a time or a distance or whatever, then okay, fine.

"But with this, you go. ‘You know, I'm actually not sure now 'cause that guy over there looks like he could do this for days.’ That's when your brain says ‘well, maybe this is not such a great idea.’"

Her goal this year is 24 hours or 100 miles (160 km). 

The winner will be given the opportunity to join 14 other runners on the Canadian National Team and compete in the World Championships, Satellite Edition in October 2022.

However, most of the runners don't see this as a competition. 

"This isn't a speed race, there's nothing even remotely fast about it … It's just about who can go farthest. Sure, everybody wants to win, but nobody really wants to beat anyone. It's not about beating other people so much as to test how far they can go. 

"It's kind of a group effort in a certain way, and I think there's something about maybe a shared suffering."

The current Backyard Ultra record belongs to Merijn Geerts of Belgium. Running a total of 90 laps. This is equivalent to a total of over 600 km, running the same 6.7 km loop every hour on the hour round the clock.

The Okotoks Outrun Backyard Ultra starts Saturday, Jul 30, at 7:00 a.m. Temperatures are expected to sit in the 30-degree range for most of the day.