Pro athletes, no matter their respective sport, take tremendous pride in their achievements. They don't want to let go of the past, so they will try to stay in the game as long as possible. Mixed martial arts fighters are no exception. However, considering the grueling and ever-changing nature of the profession, when is it time to sit back and say, "I had a great career. Let's hand over the spotlight to the newbies"?

A recent trend seen in the UFC is revolutionary fighters who just don't have that same presence in the Octagon that they once had, yet are desperately clinching on, or attempting to revive, their careers. When BJ Penn's fight with Yair Rodriguez was announced late last year, I was highly skeptical, but still just as excited as ever! Penn is an MMA legend who brought life back to the Lightweight division and proved to have one of the best ground games since Royce Gracie took to the Octagon nearly 24 years ago.

At 38 years old, Penn was banking on a career resurgence, two and a half years after his last fight (part of another career resurgence) against Frankie Edgar. Similar to CM Punk's UFC debut against a much younger Mickey Gall, the Penn vs. Rodriguez match-up was rather strange. As with the aforementioned fight, Rodriguez is a good 14 years younger than Penn (still in diapers when the UFC started). Also, the endurance of Penn couldn't keep up with the pure kinetic energy of Rodriguez' high-flying Taekwondo-based style. Despite taking a TKO loss in the second round, Penn, like Punk, still wants to fight. B.J. Penn is considered a legend and one of the best lightweight/welterweight fighters of all time. What else does he need to prove?

Speaking of fighters who may want to step away from the Octagon...

Much like what Penn did for the Men's Lightweight division, Ronda Rousey made UFC history as the first Women's Bantamweight champion, a title she held for nearly three years. Beyond that, she has made a statement: Women's MMA deserves to be taken seriously. Her frustration is understandable. She went from being the best to being an internet laughingstock. The smartest thing Rousey can do right now is walk away gracefully. She has done so much for the sport. At this point, Rousey doesn't need to prove anything to anybody. There is no doubt that she will make it into the UFC Hall of Fame. There is no doubt that young women in the profession look up to her. There is no doubt that she will continue to be successful in film and television. The only one doubting Rousey is herself.

"When your run is over, just admit when it's at its end." This line from Eminem's 2002 hit "Till I Collapse," serves as the best advice for both Penn and Rousey. If they do decide, however, to stay in the game, they need to fight consistently. You can't stay out of the ring for a year or two and expect to be champion caliber. Even with their recent losses, I think no differently of either fighter. They have earned their status and will always be seen MMA innovators.