The power of pain

This is an extended story from ESPN The Magazine's April 28 Money Issue. Subscribe today!

UNDEFEATED World Boxing Organization middleweight champion Peter "Kid Chocolate" Quillin, 30, has overcome obstacles his entire life. Using fighting as an escape from a hardscrabble upbringing and an outlet for adolescent aggression, Quillin (30-0, 22 KOs) has quickly become one of boxing's most sought-after stars. What's more, under the guidance of trainer Eric Brown, the 5-foot-11, 160-pound Cuban-American's physique has been forged by an all-encompassing, fight-focused approach. We chatted with the champ about endurance, focus and the importance of a positive support system.

Adam K. Moussa: What is the most important attribute for a boxer?
Peter Quillin: The discipline and will inside you. I can run 100 miles by making myself do that. But you have to want to get out there and do that. I have to endure as much struggle as possible during training.

Moussa: What is the most beneficial exercise for a boxer?
Quillin: Running, but it's also my least favorite. When you run and don't have headphones, you have a lot of time to think. I don't like to go into deep thought because you start to think crazy stuff. I have to put positive things in my head and be super-motivated. [But] I look at it as something that I really need, and I have to overcome the challenge.

Moussa: Do you focus on your pecs during training?
Quillin: No. That's just years of training. I've been boxing since I was 15. When you're dedicated to the gym for that long, your body starts to tell a story. To see how defined I am, it's kind of amazing.

Moussa: How do your traps assist you in boxing?
Quillin: Everything has to come together -- from the traps to the legs to the thighs. They all have to work together. Everything plays a part of the win.

Moussa: How has your training changed over the years?
Quillin: I have more say in my training and what I want to do. Now, we don't take a lot of breaks. Everything is done to re-enact a fight. Today, we did 17 minutes and 30 seconds straight on the pads. And I was focused for those 17 1/2 minutes.

Moussa: How important is endurance to a boxer?
Quillin: So important. To deliver pain, you have to put yourself through a lot.

Moussa: What is your diet like while you're training?
Quillin: I've been the same weight since I was 18, but I'm getting older. It's a challenge to make the weight sometimes. For my last fight, I made sure my weight was good by eating at Whole Foods every day. But for the whole team, that's like $300 a day for six weeks!

Moussa: How does your team assist you in your fitness?
Quillin: Everybody plays a part. Being undefeated for nine and a half years takes a good team. It wouldn't be possible without the team I have around me. I need to focus on the fighting aspect; if I go too far from that, I'd lose the fight. So my team also helps me to not have outside stuff that has nothing to do with boxing come in and interrupt me.

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