Mixed Martial Arts isn't just a young man's sport. For these 10 fighters, they fought and continue to fight well into their 40s.
It's been the driving force behind former UFC light-heavyweight and heavyweight champion Randy Couture, who has been the underdog in many of his bouts just because "he is too old."
It's been the case for almost his entire career, but when it's all said and done and Couture has his hand raised, we always can hear him saying "not bad for an old man."
The main card of UFC 129 will feature two veteran fighters who are over 40. "The Natural" will be taking on Lyoto "The Dragon" Machida, while Vladimir "The Janitor" Matyushenko will be fighting Jason Brilz; both in the light-heavyweight division.
UFC Hall of Famer Ken Shamrock is 47 and fought three times in 2010; the most in one year for him since 1996.
With a 28-15-2 record in MMA, "The World's Most Dangerous Man" has had a career that spanned over multiple organizations including the UFC, Pride FC, Pancrase, Cage Rage and Impact FC.
He won the UFC Superfight Championship in 1995 when he defeated Dan Severn and defended it twice against Kimo Leopoldo and Oleg Taktarov.
This legendary fighter is 6-11 in his last 17 bouts but still continues to fight; an option many fans are against. It may be a while before he retires, but it will probably come before he turns 50, hopefully.
Kazushi Sakuraba is a Japanese-fighting legend. Known as the "Gracie Hunter" for defeating four members of the Gracie family in MMA competition, the 41-year-old has left a mark in the sport that he entered in 1997.
He has competed in the UFC, Pride, K-1 Hero's and Dream and has fought some of the very best fighters, including Wanderlei Silva (x3), Quinton Jackson, Igor Vovchanchyn, Ricardo Arona and Jason "Mayhem" Miller.
Sakuraba's last victory was in 2009, and he is currently on a three-fight losing streak. With the adulation that comes by competing in Japan, Sakuraba probably has a few more fights left in him just to close out his career in front of his fans.
UFC Hall of Famer Mark "The Hammer" Coleman had the biggest moment of his career when he fought Randy Couture at UFC 109. Unfortunately, he lost in the second round via rear naked choke.
Before that, Coleman had made a career out of fighting and beating some of the very best fighters of his generation and the one after.
He won the UFC 10 and 11 tournaments and became the Pride FC Openweight Grand Prix Champion when he defeated Igor Vovchanchyn in 2000.
Even past his prime, Coleman continued to battle the best. He fought Mauricio "Shogun" Rua (x2), Fedor Emelienanko (x2), Mirko "Cro Cop" Filipovic, Stephan Bonnar and Antonio Rodrigo Nogueira.
Dan Severn is currently scheduled to fight twice more in 2011. The first of which will come tonight, April 29, against Ryan Fortin at a King of the Cage event.
It will be his 100th win if victorious, but the 52-year-old has had a long and extensive career competing in lower-tier organizations. The last time he fought in a premier organization was in 1997 at UFC 12.
He won the UFC 5 tournament in 1995 when he defeated Oleg Taktarov and Dave Beneteau. Since then, he has fought Pat Miletich, Jeremy Horn, Forrest Griffin and James Thompson.
The UFC Hall of Famer also competes in professional wrestling, which he does when he is not fighting.
Fifth-degree Brazilian Jiu-Jitsu black belt Murilo Bustamante has fought and trained some of the very best fighters in the sport.
We often see him in the corner of middleweight contender Rousimar Palhares, but he also made a recent comeback bout in 2010 vs. Ultimate Fighter competitor Jesse Taylor. He lost the bout via TKO in the second round.
Bustamante was scheduled to fight on an end-of-the-year card, but it never happened. His extensive career goes back to winning the UFC middleweight championship when he fought Matt Lindland in 2002.
He has also fought the likes of Dan Henderson (x2), Quinton Jackson and Ikuhisa Minowa.
He is currently scheduled to face Mamed Khalidov (22-4) at KSW 16.
Lindland won various silver medals competing in Greco-Roman wrestling tournaments as well as a silver medal in the 2000 Olympics in Sydney.
It's uncertain how many fights he has left in him, but after consecutive knockout losses, many have been calling for him to call it quits.
Jeff Monson is a two-time ADCC Submission-Wrestling World champion as well as a successful mixed-martial-artist.
He is one of the most powerful and technical grapplers in the sport and he has a 44-11 record with 23 submissions. 17 of those have come by various chokes, which is his favorite and most brutal technique.
The 40-year-old fighter is scheduled to face Maro Perak at SHC 4 on April 30. It will be his third bout of 2011 and his 12th since 2010.
Vladimir "The Janitor" Matyushenko will be fighting tough wrestler this weekend at UFC 129. It may be the most important moment of his career. The bout will be broadcast on the main card, which airs at 9 p.m ET.
Matyushenko has a 25-5 record in MMA with his only losses come at the hands of former champions Tito Ortiz, Andrei Arlovski, current UFC light-heavyweight champion Jon Jones as well as legitimate light-heavyweight fighters Antonio Rogerio Nogueira and Vernon White.
With a 6-3 record in the UFC, Matyushenko has another run for the title in him if he can defeat Brilz this weekend.
Current Strikeforce light-heavyweight champion Dan Henderson is still competing and fighting the very best in the middleweight and light-heavyweight divisions.
His recent knockout victory over Rafael "Feijao" Cavalcante was one of his most impressive. He finished the dangerous Brazilian striker in the third round with his patented "H-bomb." He has used it to knock out many opponents, including Wanderlei Silva and Michael Bisping.
If rumors are true, the 40-year-old will be fighting Russian-fighting legend Fedor Emelianenko later this year. That will be a true battle of legends that nobody will want to miss. It will be the defining moment of Henderson's career.
Even at 47, Randy Couture remains one of the most motivated and inspiring athletes in the sport.
He has had more title fights than anyone in the UFC, and it's part of what makes the Greco-Roman wrestler so fascinating to watch.
The three-time former UFC heavyweight champion and two-time former UFC light-heavyweight champion will be making his final appearance in MMA this weekend when he takes on Lyoto "The Dragon" Machida.
If it is truly his last bout, expect to see 55,000 fans in Toronto, Canada cheering the UFC Hall of Famer as he makes his final walk to and from the cage.