Neither B.J. Penn nor Renzo Gracie need to prove anything by fighting again.
Except to themselves.
"I want to see how we go into the mid-30s," Penn, 34, told Newsday. "I want to see, maybe this is the best we're ever going to be. We're going to find out, that's for sure."
Both Penn and Gracie possess enough accolades in Brazilian jiujitsu and mixed martial arts to last a lifetime and beyond.
Still, they choose to fight again rather than retire -- a decision many MMA fighters struggle with.
"If someone else makes it for you, you're never going to be happy," said Chuck Liddell, a former UFC light heavyweight champion who retired in 2010 at age 40.
Penn (16-9-2) emerged from a second pseudo retirement to be a coach on the next season of "The Ultimate Fighter," which is being recorded now for broadcast early next year. He is coaching against Frankie Edgar, the man who took Penn's lightweight title and held onto it in the rematch as well.
Penn doesn't like that.
"This is one time, I want to fight him now, not he wants to fight me [because] I'm the champion," said Penn, one of only two men in UFC history to win a title in more than one weight class. "I want to fight him. That's what it is."
Penn is 1-2-1 since that second loss to Edgar. After losing a one-sided decision to Nick Diaz in October 2011, he debated fighting again, only to return 14 months later for an even greater one-sided decision loss to Rory MacDonald.
Also roaming around the TUF tapings is Gracie, a BJJ legend. He is helping Edgar coach his team of young fighters.
Several weeks ago, Gracie said he planned to return for another MMA fight in February or March of 2014. Gracie turns 47 on March 11.
"I do believe fighting is the most important thing to push yourself forward, to make yourself better," Gracie said. "I don't fight just for the money or just to become a champion. I fight because every time I fight, I improve myself as a teacher, as a fighter, as a way to show other people ways to do things. I'm able to teach them -- my students and the people I train -- to be better."
Gracie owns four BJJ academies in the tri-state area, including one in Manhattan and one in Brooklyn. UFC champions Chris Weidman and Georges St-Pierre are among those who train there.
Gracie doesn't care that UFC president Dana White -- and many others -- publicly questioned why he wants to fight competitively again. Gracie looked outmatched in his last fight, a TKO loss to Matt Hughes with 20 seconds left in the third round at UFC 112 in Abu Dhabi in April 2010.
"I do what I feel my heart tells me to," Gracie said. "It's not about winning or losing anymore. Now it's just about doing it for the real reason -- I love it. I would do it even for free."
Gracie mentioned One FC, a prominent MMA promotion based in Asia, as a possible place to fight. He gained much of his popularity fighting for Pride in Japan in the late 1990s and early 2000s. Perhaps his most notable fight there came in defeat in August 2000 when he refused to tap out to a kimura submission, thus allowing Kazushi Sakuraba to break his arm rather than concede defeat.
When Gracie disciple Matt Serra, a former UFC welterweight champion from East Meadow retired from competitive fighting last May, he couldn't bring himself to use the "R" word. During an hour-long conversation two weeks shy of his 39th birthday, Serra could only use the phrase "walk away."
Walking away from an athletic career is never easy, regardless of the sport. The cheering stops. There's nothing to train for, nothing requiring a three-month regimen. The recognition from fans continues, but the interest level wanes.
The adrenaline rush from being on center stage can be like a drug to some fighters. And when that gets replaced by the reality of that moment no longer being something to experience, the adjustment period takes time.
"You went 30 years of having something coming up soon, training for something, now you're not training for anything," said Liddell, the UFC's first mainstream crossover star. "You're out there, you're just trying to figure out where you're going."
Liddell struggled with the idea of retiring. After a first-round TKO loss to Mauricio "Shogun" Rua at UFC 97 on April 18, 2009, the belief was that Liddell would retire. White was emphatic that Liddell was done.
But on June 12, 2010, there was Liddell -- inside the octagon for UFC 115, holding his own against Rich Franklin until the final seconds of the first round. A right hook from Franklin ended the bout -- and Liddell's fighting career. Six months later, after 21 wins in 29 professional MMA bouts, "The Iceman" was done.
"When I decided, I told Dana, 'Can you wait a couple months to announce it?'" Liddell said. "I wasn't ready to say it. I made the decision, but I'm not ready to go out and deal with telling people I'm not fighting anymore. So we waited three months to announce it."
The decision to retire rests with the fighter first, regardless of interest from a promoter. The decision to once again step into a cage to challenge yourself against someone else in a combat sport involving all four limbs begins with the fighter, as well.
"What is life but defying the odds?" Gracie said. "The secret to be a true champion is to never quit. I'll be 60 and still thinking about beating up someone, in a poor man's event, in a ring set up in a bar, who knows? It's what drives me."