The Calgary Marathon is holding a special event this year to celebrate its 50th year — a 50 kilometre race.

Organizers will also be offering $50,000 in prize money to the more than 15,000 participants expected to hit the pavement this weekend.

Calgary lawyer Adam Campbell

Calgary lawyer Adam Campbell, who plans to run the 50-kilometre race this weekend in a super hero costume, holds the world record for running the fastest marathon in a suit and tie. (Courtesy Adam Campbell)

"It's really novel for one, that a big city marathon is going to have an ultra marathon at it,” says Calgary lawyer Adam Campbell.

The two time Canadian ultra-runner of the year has been spending up to 30 hours a week training for the race.

"I'm generally running twice a day, pretty much every day of the week,” said Campbell, who normally runs mountain trails.

"It's a lot of training for sure."

Campbell will be easy to spot, he'll be running in a super hero costume, in honour of Kidsport.

"It's a great charity, I'm a huge advocate for any sort of active living.”

Campbell has dressed up for a race before — he holds the world record for running the fastest marathon in a suit and tie.

Biggest event yet

Calgary Marathon

The Calgary Marathon is the oldest, continually run of its kinds in Canada that has been organized by the same group. (Calgary Marathon)

The 15,000 runners are expected to make this Calgary’s biggest marathon yet.  

Executive director Kirsten Fleming says that's almost 30 per cent more participants than last year.

"The trajectory of growth has just been exponential and we do feel we've hit that critical mass where we will just continue to grow at that pace.”

And when it comes to big city marathons there are larger, and faster, races in the country, but few have as much history.

Calgary is the oldest, continually run marathon in Canada organized by the same group.

1972 Calgary Marathon

Runners take off at the start of the 1972 Calgary Marathon. This year's races are expected to be the largest ever, with 15,000 participants. (Calgary Marathon)

With files from Kyle Bakx/CBC