Thousands of runners will hit the roads of Minneapolis and St. Paul in the Medtronic Twin Cities Marathon on Oct. 7, an ordeal that takes the vast majority of citizen athletes three, four or five hours to complete.
Until recently, the idea that a human could run 26.2 miles in less than two hours was inconceivable. But back in 1991, one guy said it was theoretically possible.
At the time, Michael Joyner, a former college runner with a medical degree, a residency at the Mayo Clinic and an interest in the limits of human endurance, wrote a paper suggesting that a man with the ideal physiological traits could break the two-hour marathon barrier by more than two minutes. That would be nearly nine minutes faster than the marathon record in 1991.
"People thought this was nuts and it took a while to get the paper published," Joyner would later write.
Recent events have shown that Joyner, now on faculty at the Mayo Clinic, wasn't so crazy. The official marathon record now is 2:02:57, but in May 2017, a project called Breaking2 staged by Nike saw Kenyan runner Eliud Kipchoge finish the distance in 2:00:25 with the aid of a closed track, specialized pacers and custom shoes.
The once impossible two-hour marathon barrier no longer seems so far-fetched.
After writing his 1991 paper, Joyner set up a lab at the Mayo Clinic to study the physiology of elite athletes. He's been a consultant for NASA. He's a frequently quoted source about human performance for places like the New York Times and PBS. In addition to publishing studies in academic journals, he's written for Sports Illustrated and Outside magazine.
It wasn't the path Joyner, 60, was on when he started college at the University of Arizona. He was a good track and cross-country athlete (14:38 for 5,000 meters, 30:48 for 10,000 meters, 2:25 for marathon), but a poor student. He was considering dropping out and trying to get a job as a Tucson city firefighter. But then he was recruited to be a subject in an exercise science study on lactate threshold and anaerobic threshold.