When you reach the highest achievements in your sport, the next goal is to find new ways to challenge yourself. For some, that’s maintaining that level. For others, it’s adding to it.

Claressa Shields has one of the most impressive boxing resumés of any woman. She’s 11-0 with two knockouts. The nine other wins were all via unanimous decision. Shields is also a two-time USA Olympic Gold medalist, the only boxer to hold the four major belts – IBF, WBC, WBA, and WBO – simultaneously, and the only undisputed champion ever in two weight classes, light middleweight and middleweight.

And she’s only 26 years old. Seriously, what’s left for her to do?

“It’s not that there’s not more opponents to fight, but what more records can I break?” Shields said in a recent Zoom interview. “I’m a 12-time world champ. If I became a 20-time world champ, what would change? Nothing.”

Shields can only maintain her status, so she’s gotten creative in how to add to her historic resumé. She signed with the Professional Fighting League and picked up MMA. Her first fight will be June 10 in Atlantic City.

The Flint, Mich., native has been learning mixed martial arts since last year. She had offers galore, but she had to be smart. Some promoters wanted her to come right in and fight the elite. Shields signed with the PFL because it gives her the best chance at success while allowing her to hone her craft.

“When I turn 28 or 29, I can be a very established fighter,” Shields said.

“The PFL seemed like it was the most fair,” Shields said. “They had the 155 [pound] weight class, [superstar] Kayla Harrison, and a million-dollar tournament. A lot of these companies wanted me to go train wherever for six months, and then get in the ring with their best fighter. And to me, that’s setting me up for failure because I really respect the sport of MMA.”

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Shields will debut against Brittney Elkin (3-6). After that, she’ll analyze the result and prepare for next season, when she could be ready to face the best of the best and compete for the $1 million PFL prize.

Learning MMA hasn’t been easy, and when you factor in Shields is doing it while trying to hold onto her boxing belts, it’s an unimaginable amount of practice. One day she’s boxing. Then it’s mixed martial arts. She’s been training at the Jackson Wink MMA Academy gym in Albuquerque, N.M., since December.

One of the people Shields has sparred with is Holly Holm, who is one of the few successful examples of transitioning from boxing to MMA.

“I’m starting to understand what kind of fighter I’m going to be in the cage,” Shields said. “I’m going to use a lot of my boxing, and I’m going to use my big strong legs to kick. The most difficult part has been putting it all together. It’s really hard to go from one minute you’re boxing, and the next minute you’re sprawling on the ground,”

Shields’ goal is to become an MMA and boxing champion simultaneously. Even for a woman widely regarded as the greatest female boxer of all time, that’s a tall feat. But the GWOAT wants to climb the ranks, challenge herself, and make more money. This is her best shot.

“Everybody here at the Jackson Wink gym are like, ‘We believe you’re going to be a great MMA fighter, and you can become a champion’ ” Shields said. “I’m just looking forward to it.”