Ashton Eaton throws off the uniform

Ashton Eaton set a world record at the 2012 U.S. Olympic Track and Field trials for the decathlon. Carlos Serrao for ESPN The Magazine

Why did you decide to pose for the Body Issue?
AE: I struggled with it at first, but I talked with my mom and my fiancée [heptathlete and Canadian Olympic hopeful Brianne Theisen], and they said it was classy. I think it's good for the sport and done in a way that represents athletes well.

If you could write the caption for your photo, what would it say?
AE: "What you see is a depiction of what I want to accomplish and how I want to do it." My body is the way it is because there is this thing I want really badly -- Olympic gold -- and the things I have to do to attain that have crafted what you see.

Why do you want to be the best?
AE: The desire definitely comes from within. There are only a few people who make it to this level and those are the ones who have that innate desire. I want to see where I measure up against everyone in the world and everyone who has ever competed in the sport, and there's that innate sense of wanting to challenge myself. I'm competitive in all aspects. When I drive, when I play video games, when someone says, "Hey, can you do an under-the-leg 360 dunk?" When someone gives me a realistic challenge, I won't back down. I get a satisfaction from being tested and defeating the test.

How did you become such a well-rounded athlete?
AE: I'd see something on TV and want to copy it. I remember seeing the long jump on TV and thinking, Wow, that is so cool; I can do that! So I'd jump over fallen trees and copy what I had seen. I would set up sticks and jump from one stick to the other until I couldn't reach. I was doing this well before I knew what track and field was.
I started doing taekwondo when I was 7. I did that for six years. Martial arts helped me in a lot of ways, mostly mentally. That was the first sport where I was asked do something I didn't think I could do. It had nothing to do with the fighting, but we'd break bricks and boards. ... Martial arts instructors are very persuasive, like drill sergeants, so I learned I could push my body to do stuff or conquer things I wasn't initially comfortable with. That helped with track when I got to college and had to do pole vault and hurdles. I first got good at hurdles when I started trying to kick them like it was taekwondo practice. For some reason the technique clicked, and I ended up sailing right over the hurdles.

What's the best and worst part of decathlon?
AE: The thing I like is also the thing I dislike: There are 10 different events. If it were just a 100-meter run, eventually I'd reach a top speed and that would be that. But I have all these things to get good at. It's the maximum challenge, and if the results are good it's maximum satisfaction. But it's also maximum frustration because it's not possible to be that good at everything. Everybody has a limit; my body in each event will be limited.

Do you feel the winner of the decathlon is the best athlete in the Olympic Games?
AE: Yes. There are definitely athletes who don't do decathlon but would be really good at it, but decathlon is the test to determine the best all-around athlete. We run, jump, throw implements, hurdles, pole vault. It's like the SATs of athletics.

Describe your toughest day of training.
AE: We'll come in at 10 in the morning and do a throw, like shot put, a running event and long jump. We'll come back for another two-hour session and do pole vault and 400-meter training, which is speed endurance. Then we go to the underwater treadmill and do some running for a cooldown. Monday, Wednesday, Friday usually focus on running and jumping. Tuesday, Thursday and Saturday are lifting and throwing. In the first part of the season we'll do some heavy stuff, but as we get closer to competition it becomes a lot of lighter, quicker stuff that's based on all-around fitness. We aren't trying to gain too much muscle, just trying to be strong and explosive. So we'll do your basic bench press, squats, power cleans and then auxiliary lifts with dumbbells: curls, triceps, shoulder circuit, box jumping with weight on our back to fire up the legs. And abs are always included.

What's the most unusual training you have ever done?
AE: Playing basketball -- it's high jump practice. We'll dribble around, shoot around, go into layups and then try to dunk -- over and over so you can get the feel and rhythm of the high jump. On style I get a zero, but I can do it.

When you hit a wall, how do you move past that point?
AE: If I've already done something, then I think I can do it again and I can do it better. But my body has never hit that point. I haven't died yet and I haven't felt anything close to dying. That's what it would take for me to stop.

What is the one exercise you can't live without?
AE: Pole vault. It incorporates aspects of every event. There's a lot of timing involved as far as your steps and takeoff. You get a lot of shoulder work in and there is a lot of general athleticism involved. And like every event, it's very rhythmic.

Was there any point when you thought pursuing decathlon wasn't going to work out?
AE: I've never thought it was guaranteed, but I never thought it wasn't going to happen either. I didn't think, I'm going to go to college and do sports and track. But I never thought I wouldn't. I've never thought about going to the Olympics or not going. It's almost like if you assume you are, you don't really think about it at all.
I didn't know how good I was out of high school, but once I performed really well someone said, "Wow, you can win NCAAs." I was like, Okay, that's the next benchmark. After I won, someone said, "You are good enough to go to the Olympics." Okay, that's the next test. I'm always moving on to the next thing, like steppingstones.

What body part do you neglect because it isn't important for your sport?
AE: We don't do a lot of back work. Our workouts are done with injury prevention in mind, and the last thing we want is to hurt the back, so it's just not worth it.

If asked to compete in another Olympic sport, which one do you think your body would allow you to be most successful in?
AE: I would excel in martial arts, taekwondo. I'm a black belt.

In which sport would you embarrass yourself?
AE: I would get absolutely dominated and embarrassed beyond all reason in swimming. I love swimming, but I cannot swim more than 200 meters without needing some kind of life-saving apparatus. It takes me more energy to swim 200 meters than to run twice that distance. Even treading water is difficult for me. I think I just get tense in the water. My calves start cramping up. I know how to relax when I run and I can be smooth, but once I start swimming it's like I'm fighting lions. My friends laugh at me -- "You are potentially an Olympic medalist and you can't swim 200 meters?"

What about your body would surprise us?
AE: I've been told my legs are extremely heavy for how small they look. Physical therapists always say, "Man, your legs are really heavy." My abs aren't weak, but I can't do leg lifts at all. I start sweating after 10 seconds. I don't know why. My legs don't feel heavy when I run.

What are you looking forward to most once London is over?
AE: My fiancée and I are going to travel all over Europe and see the cities and eat food from every country. Europe has so much history and cool stuff -- castles and old cathedrals. We're planning to leave straight from London, go north to visit Scotland and then hit the Eastern bloc, the Mediterranean and everything in the middle. It'll probably take three weeks to a month. And heck no, there will be no working out. After track season is over, no one does anything for a month. Most people take six to eight weeks off, but decathletes take 12. As far as I'm concerned, rest is training. You need a mental break. This whole year I've been on edge because in every competition I'm trying to do the best I've ever done. It's an Olympic year. I think once I cross the finish line and it's over, it's going to be a big "whoosh!" So much weight is going to be lifted: Yes, I've been here. I've accomplished what I wanted! And then my whole body will shut down.

Follow The Mag on Twitter (@ESPNmag) and like us on Facebook.