Scott Jurek, left, has raced the famously talented Tarahumara Indians in Mexico’s 50-mile Copper Canyon Ultramarathon.

Scott Jurek always goes the extra mile — and the mile after that. Since his first ultramarathon (that’s any race longer than 26.2 miles) in 1994 when he was 20, the Midwesterner has notched an exhausting-even-to-look-at list of performances, including his completion of 165.7 miles at the 24-Hour World Championships race in 2010. In his new book, “Eat & Run,” Jurek shares stories from his extraordinary career and explains why he sticks with a strict vegan diet. He’ll be at a fun run and signing in Arlington on Friday (the run starts at the Nature Conservancy headquarters at 6:30 p.m.; the signing at Pacers starts at 7:30 p.m.; visit for more information).

What makes you run ultramarathons?

Initially, it was a dare from a buddy. I didn’t have this idea that I was going to become a professional ultrarunner. But basically, nowadays, I look at it as a way for me to explore the human potential in me.

Was there ever a moment when it clicked for you, when you knew that ultras were your thing?

It took a while. The first time I finished, it was like, ‘Never again’ — much like a lot of people after their first 5K or 10K or half-marathon. But it was this gradual realization.

How might somebody else know if they are ultra material?

I think everybody’s ultra material. We all have that ability. Humans were meant to run long distances; we all have that endurance capability. You don’t need to be an amazing athlete. You just need to have the will.

And the time to fit in the training?

I know runners who run 100-milers who have careers, very stressful jobs, families, and they run 100-mile races on 30 miles a week [of training], so you don’t need a lot of time. But if you want to place at the top and if you’re going to win, sure, you have to put the time in.

What’s your training like?

I’m not out there four or five hours a day, like a lot of people assume. We do back-to-back type training, so you run two long runs on back-to-back days. I might run 20 to 30 miles on Saturday and then another 20 to 30 on Sunday. That’s how you replicate 60, 70, 80 miles into a race; you want your legs to get fatigued and develop a fatigue resistance. But during the week I get on the track, do short interval workouts, tempo threshold runs and hill repeats. And then I mix in strength training, core training, yoga.

As a vegan, do you have to take any special considerations to be sure you’re eating enough?

Not at all, surprisingly. There are plenty of great fats and calories in nuts, nut butters, tempeh, tofu, legumes and grains that provide enough protein. It’s a little tricky when traveling in remote areas, but it can be done. I actually enjoy the challenge sometimes.

Since you spend so much time running long, what’s it like for you to run a short distance, say a 5K?

Oh, if I race short distances, it’s just as hard. It’s a lot less time, but the discomfort and how hard you work … that can be just as challenging as sometimes running 50 miles at a shot. It’s not like a walk in the park.