Is breaking the 2-hour barrier for running a marathon even possible?

Two hours, two minutes and 57 seconds — the fastest time to complete a marathon. 

It has taken 100 years to get to this world record set by Kenyan runner Dennis Kiletto in 2014. 

And now, a new project by Nike aims to break the two hour barrier in a special marathon planned for the spring.

For a sport where records fall by seconds — not minutes — skeptics are questioning the possibility a human can even achieve this feat.

Canadian Olympian and marathon runner Reid Coolsaet tells The Current's Anna Maria Tremonti the quest to break the two-hour barrier is exciting but he's not hopeful.

"It seems like it's on the horizon but I always felt that it's probably about 25 years away to do it — you know, a record eligible course."

Coolsaet's best time is 2:10:28. He says his fastest six times in a marathon are all within one minute of each other.

"I'm trying to update my training and become a better athlete all this time, and I'm taking maybe 20 seconds off every couple of years," he tells Tremonti.

"It's really hard to find these gains once you're already pushing the limits and training and racing."

Alex Hutchinson, a columnist for Runner's World, is one of only two journalists covering the Nike project. He explains to Tremonti that the quest involves controlling as many variables as possible to reach the sub-two-hour goal.  

"[Nike] thinks they can change or control a few things, both environmental, in terms of how the race is run and where it's run, and in terms of how they outfit the athlete."

While the location hasn't been determined, Hutchinson explains the race will be a closed course which is flat and as controlled as possible. They will pick the time of year and exact start time to make sure weather conditions are perfect. 

"And pace makers … will lead the runners in exactly the right pace and block them from even whatever air resistance is remaining. So all these factors that are already sort of controlled in track races have never really been controlled in road races like a marathon."

Dr. Michael Joyner has been at the forefront of research into the phsyiology of marathon runners. He's a researcher at the Mayo Clinic in the U.S. and his 1991 landmark paper was the first to suggest it might be possible for someone to run a marathon in under two hours — given optimum conditions.

"What I did back in '91 is just simply say what would happen if one person had the best values for maximum oxygen consumption — something called the lactate threshold  — and running efficiency and they were all rolled into one person and that's where I came up with my numbers."

Joyner tells Tremonti that one area where East Africans have stood out as runners is they tend to have a better efficiency than athletes in other parts of the world.

Over the last 15 to 20 years, Joyner says the professionalization of marathons has led to the sport becoming very globalized.

"So the incentives are aligned to get people to run faster and faster and faster. And I think then there's always the dark side of this … the extent to which doping might or might not be contributing to some of this."

Listen to the full segment at the top of this web post.

This segment was produced by The Current's Willow Smith and Samira Mohyeddin.