As he pummels opponents inside the ring, Marcus Browne beats himself up outside of it for even being in this position.
The light heavyweight should be sitting on the sideline and taking in the bouts, not bobbing and weaving at the U.S. boxing national championships this week.
It's Browne's Olympic spot that his challengers are chasing after, the one he let slip from his grasp.
And that constant reminder only riles up Browne even more.
See, Browne captured his weight division at the Olympic trials last summer, putting him on the path to represent the U.S. at the 2012 London Games. All he had to do was finish high at the world championships and he was on his way.
But he didn't and surrendered his spot, leaving it up for grabs again.
He hasn't felt pain like that since, well, the first time he took a punch to the stomach as a 13-year-old in a Staten Island, N.Y., gym. That blow nearly sent him scurrying for the exits, tears welling up in his eyes.
This blow simply sent him scurrying back into the ring, eager to prove he was still king of the canvas.
Sure, he's upset about having to earn his spot back here at nationals, but he figured he had two options: Keep pouting or start punching.
"I'm treating this as redemption, as Operation 'Get-my-spot-back,'" the 21-year-old Browne said. "These guys are just keeping it warm for me. I'm definitely getting my spot back."
Browne certainly doesn't lack in confidence. Never has, really, ever since venturing into the ring as a teenager and taking that first blow to the gut.
He only showed up because he happened to idolize one of the toughest kids on his neighborhood block, Nwachi Hartley. Four years older, Hartley, who was known as "Speedy," was passionate about boxing.
So Browne followed in his footsteps as Hartley taught him the ropes.
But Hartley's no longer around to teach those lessons and dole out those helpful tips. Hartley died in a car accident in 2008.
Mention Hartley's name and Browne's ever-present grin instantly fades. He misses his friend. He misses their chats.
"I do fight for him when I'm in the ring," Browne said. "Most definitely, I do."
He could've used Hartley's comforting shoulder, his uplifting words of wisdom last year.
Browne was flying high after winning the trials, only to tumble back down at worlds in Baku, Azerbaijan, when he lost to '09 heavyweight world champion Egor Mekhontsev of Russia.
With it went Browne's ticket to London.
After worlds, he took two weeks off to get his "mind right."
And what's emerged from the gym is a different fighter, a much more determined one.
He may be beating himself up about having to win back his spot, but he's also taking care of business in the ring.
"Being here, it's stressful," said Browne, who, if he wins this weekend, still has to finish in the top four at a qualifier in Brazil this May to earn an Olympic spot. "I ask myself, 'Why am I here? How did I let this happen?' At the end of the day, I am here. So I've got to do what I have to do. I've got to get the job done."
This newfound clarity is coming from a maturing boxer who refers to the younger version of himself as a "knucklehead."
Growing up, he was a little bit of a bully. Nothing major, just wanted to let everyone know he was someone to respect.
Like the time he walked straight into the middle of a neighborhood soccer game and grabbed their ball. He then informed all the stunned faces gathered around him that if they wanted their ball back, they had to take it.
Naturally, they all pounced and yet struggled to pry the ball away. Browne heartily laughed at the memory.
"I picked fights for no reason," he said.
Soon after, he began honing his talent in the gym, under the watchful eye of his trainer, Gary Stark Sr.
Steadily, Browne rose up the ranks and captured the national Police Athletic League championship in 2010. That helped put him on the map as a force to contend with. He's been on the ascent ever since, relying on a mixture of speed, power and a healthy dose of self-confidence.
His biggest hurdle this weekend? Easy.
"I'm my biggest obstacle," Browne said. "If I don't do what I'm supposed to do, I'm not going to win. If I do what I'm supposed to do, I'm going to win. It's that simple."
Follow AP Sports Writer Pat Graham on Twitter: http://twitter.com/pgraham34