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.

Fascinated by the lab work, he started improving his grades and went to medical school at Arizona.

Now he’s “one of the world’s most widely cited experts on the limits of human performance,” according sports science journalist Alex Hutchinson.

Later in life Joyner went from being a fast runner to a fast swimmer, competing at a national level in masters events.

In an interview we’ve edited for clarity and space, we asked Joyner about the two-hour marathon, the mind-set of elite athletes, his advice to runners in the form of a haiku and his favorite nonhuman athletic performance.

In 1991 you said someone with the ideal physical attributes could run a sub two-hour marathon. What was the number you came up with as the potential time and how did you determine it?

1:57:58. I’d been thinking about lactate threshold, running efficiency and VO2 max. When I was in medical school in 1987, I got a programmable calculator. A motivated person with a programmable calculator and a yellow legal pad can do a lot of damage. Just running thought exercises with myself, I finished the calculation at a physiology seminar before I left for Mayo and I wrote it up and eventually it got published. But the thing people forget is, this was not a prediction. It was a model to help us understand what we didn’t understand at the time.

What was the reaction?

People thought it was interesting. People thought, you know, wow. Other people would read it and talk about it from time to time. But really, the paper lay somewhat dormant for about 20 years. And then in the late 2000s and early 2010s, people started to take big chunks out of the marathon record. In 2011, we revisited the model and made an additional prediction. And things continued to take off and of course Nike had their little effort last year. I would give talks about it from time to time. People thought it was an oddball and interesting thing and the idea became less crazy as time progressed.

Back in 2010 you were suggesting that a two-hour marathon could happen in another 12 to 25 years.

We thought it would be somewhere in 2020 to 2030. Not necessarily break two hours, but get somewhere near 2:01.

Right, you said that could be reached with a flat circuit course, a cool windless evening and prize money at stake. And now we’re at 2:00:25. Was it the shoes?

If you look at what Nike did, I think there’s a number of things that happened. One is, drafting played a big role, people sort of running like a flock of birds, in a V-shape. I think that certainly helped, both physically but also psychologically, so somebody doesn’t have to do all of the pace work. The temperatures were cool but not ideal. There’s a lot of speculation by people like me that if it had been four or five degrees cooler and a little bit drier, [Eliud] Kipchoge might have gone a little bit faster. He was a second a mile off. He faded a little bit in the last five kilometers. He might have done a little bit better if it had been just slightly cooler. But we’ll never know.

Isn’t there a big mental component that governs athletic performance? Doesn’t the athlete have to believe that the two-hour barrier can be beat?

Sure, there’s a big mental component. But I think once you get to the elite of the elites, you’ve selected for that. Either they’re that way before they start training, or through the process of years of running 100 miles a week, they become not so much mentally tough, but they learn how to manage their suffering.

Every once in a while, you hear these stories about a person who uncorks a performance that is beyond what was expected. What’s going on there? Did they unlock something in his or her brain? Or was it drugs?

Yeah, that’s always the $64,000 question. Is it drugs? But certainly I’ve seen a number of these. Bob Beamon’s long jump when I was a young kid comes to mind. What Katie Ledecky is doing in the pool. Secretariat winning by 30 lengths in the Belmont Stakes in the greatest endurance performance of all time, animal or human. I would encourage you to go watch the clip and hear the call of the great track announcer, Chic Anderson. Chills will go up and down your spine. So you see those sorts of things. People making these big drops. Less now than you used to. Certainly Usain Bolt, Michael Johnson recently have done things. And you never know how much of it is the person versus how much of it is improved technology. The tracks are better. The shoes are better. The classic example being the pole vault poles. Sometimes somebody develops a new technique like the Fosbury flop.

Remember for many years in these sorts of sports people did not have long careers because there wasn’t a way to make a living. And now people have these extended careers. Once no swimmer had ever participated in more than two Olympics because it was not a profession. The idea there would be swimmers going into their late 20s or early 30s was seen as absurd. And now in non-Olympic sports we have people like Tom Brady and others who are going to try to play forever.

How are elite athletes different from the rest of us mentally or in their personality?

I think that they’re like a lot of people who are virtuosos in anything. They found something they’re good at. It gives them a great deal of personal satisfaction. And they’re able to retain their focus on it and it captivates their imagination. And frequently they’re in some sort of microenvironment or microculture or subculture where they get a lot of positive feedback for it, where they eat, breathe and drink it. It really becomes their world.

What marks these individuals is the fact that the will to prepare to win is equally important as the will to win. We’re seeing a classic example of it now with LeBron James. The guy is 33 years old. He’s been playing in the NBA for 15 years and he’s getting better.

What is the role of the brain in great athletic performances?

I don’t know if the word meditation is correct, or altered state, but through this sort of high discipline of the athlete, people learn how to both relax and put forth the maximal effort at the same time. And that’s the real paradox of elite performance, really at anything that’s physical, including the arts, music and so forth. How to learn to put forth the maximum effort and relax and manage their suffering.

There’s a very famous coach called Bud Winter. And Bud Winter had trained fighter pilots in World War II as a physical educator, and he noticed that people who were able to focus and relax while they were dogfighting did the best. He developed a series of form and relaxation drills that he instituted at San Jose State University, where he coached a huge number of world-class sprinters and other athletes. He also coached a Jamaican who went on to coach Usain Bolt’s coach. There’s kind of this cult classic book out there by him called “Relax and Win.”

Bud Winter was a New Age Yoda before anybody heard of him: don’t think, do. You see this in team sports when they say that certain teams are playing downhill, where you see this tremendous focus. Secretariat gives you that perspective, when you watch that race, of tremendous rhythm and power. You see that with Katie Ledecky. You certainly see it with Michael Phelps in his great races. You see it with Bolt. You certainly saw it with Kipchoge when he was running just over two hours for the marathon. This tremendous effort but relaxation at the same time. You see it when Steph Curry hits those wild jump shots.

Has your career studying elite athletes and elite performances changed how you manage your own life?

I have this absolutely wonderful life. My only regret is I can’t go to practice every day at three o’clock anymore. I wish I could and be with my friends and my wonderful coaches and do these amazingly brutal workouts. You really kind of miss not only what you were doing physically but also the tribalism. But I think what you learn from elite athletes is to be a maximalist you first have to be a minimalist. What these folks are really good at is getting rid of distractions and identifying what’s important and focusing on it. The other thing that they’re good at is training super hard, but they also understand the concept of recovery, that you can’t train hard every day or every week. Which has led to my running haiku.

What’s your running haiku?

“Run a lot of miles. Some faster than your race pace. Rest once in a while.” And it’s five-seven-five for those following in Japanese. My favorite race ever is the 5,000 meters at the Tokyo Olympics where a guy named Bob Schul, who did nothing but interval training, won. He barely beat a man called Harald Norpoth from Germany, who did nothing but long, slow, distance running. He barely beat Bill Dellinger, who for many years was a track coach at the University of Oregon. Dellinger kind of did mixed modern training. There are many ways to get really good at things. I have a weight loss haiku too: “Fewer calories. Increase your activity. Adhere to a plan.” Things are incredibly simple, just hard to do.

For many Americans the problem is inactivity. In 2012, you suggested that doctors identify lack of conditioning as a medical diagnosis, something that should be treated with exercise. Are we getting the message?

I think that most people know it. But I think it’s very hard in our obesogenic environment for people to do it. We don’t have enough bike paths. We’re addicted to cars. It’s possible to wander into any number of fast-food places and for a few dollars get 1,000 or 1,500 calories of food. We’ve really got to think about those sorts of things and look at this the way we looked at sanitation many years ago as a primarily environmental problem. I think there’s always going to be 10, 20, 30 percent of the population who will follow the guidelines and have the means and the conscientiousness to take good care of themselves, but I think for a lot of people, it’s most challenging.

For the thousands of citizen runners who are going to be hitting the road next Sunday in the Twin Cities Marathon, what’s your last minute advice?

Don’t go out too fast. Especially for the men. I published a paper with Rob Deaner, Sandra Hunter and Rickey Carter where we looked at about 100,000 marathon finishes and we showed that especially among men running around three and a half, four hours, they are far more likely to go out way too fast than women and really buy the farm or explode in the second half. Women were much better pacers than men. But those sex differences disappeared among the faster runners. There’s a lot of ways you can look at it. One, it confirms that women are smarter than men. But certainly typically, among the mid-pack and recreational runners, women in general do a much better job of managing the race on average. 