They call her T-Rex.
"Back when I was younger, I was very skinny and I had short arms, but I used to always be swinging. I was always swinging. I was also kind of smaller than everybody else and I was really aggressive, so that's how I got the nickname T-Rex," says Claressa Shields, the 2012 London Olympics boxing gold medalist.
But Shields is not the old T-Rex she used to be. She still swings her arms, but now they have a lot more force and training behind them.
"The advantage for me is even though [other fighters] are taller and longer, I'm very slick, I'm very fast and I punch harder than them," she says. "Also, my footwork and foot speed allow me to get to them on the inside when they are moving and running. So now I don't have problems with taller fighters anymore. I don't have problems with shorter fighters, and I don't have problems with fighters my size. I've checked all my boxes so that no matter who I get in the ring with, I'm always prepared."
She took a break from her Rio Olympics preparations to sit down with ESPN The Magazine for the 2016 Body Issue and share how she's training to try and repeat gold.
It's all for boxing
According to Shields, her life has always revolved around boxing.
"I started boxing when I was 11, and ever since my whole life has been about boxing," she says. "Everything I do has been about boxing. I played basketball so I could be in shape for boxing, I ran track for boxing. It gave me a little joy winning some competitions, but everything I did was for boxing. I didn't even go to the beach until I was freakin' 14."
Her training gets very intense, but it is worth it to her to prepare. "Once I walk into the ring, the only thing I'm thinking is, 'I've trained for almost six weeks, I'm pissed. I've done too much training to lose.' That's where my mind is at," she says.
Early mornings: "I start my day at 7:30 a.m. every day except Sunday. I have to get up and weigh in with our coach. He wants to check our weight every morning. We eat a little meal, and then we have strength and conditioning at 8:30 a.m."
Long sessions: "We lifts weights, body weights, pushups, lunges. We do a lot of sprinting and long distance running and after that we'll still do weights. It's like an hour and a half worth of training."
Shields says she trains seven to eight hours a day, which leaves her body very sore.
"I'm always doing extra," she says. "Even though the coaches will tell me, 'You only got 10 rounds,' me being an Olympic gold medalist I always stay after, I always hit the bag after, I always do pushups and crunches after -- or I might even go for another run. For some others it's probably five or six hours, or maybe even four, but for me it's seven or eight."
With all of that punishment on her muscles, she gets massages three to four times a week to give her body a break.
"You know how you are supposed to sit straight up?" Shields says. "My back kind of comes in a lot because of how much I train, and how I'm trying to keep my guard to protect my body and to protect my face, so I kind of round everything to the punch. So that causes problems for my back."
Boxing makes Shields excited, so much so that her family and friends think she is a little crazy. But Shields uses her excitement to pump herself up before matches.
"I'm excited to fight anybody and everybody, especially the girls who say that they can give me a run for my money," she says. "I'm so ready for this! You don't even know. I'm super ready."
This summer, espnW is running stories, essays and letters on body image as part of a series called "Love, My Body." Read more from the series »