Chael Sonnen might not carry himself in the most idealistic ways, but even his most vocal detractors have to admire his self-confidence and work ethic. Though he does have his weaknesses inside the cage, namely his infamous submission defense that has plagued him in eight of his 11 career losses, Sonnen has a drive unlike any other middleweight in the world.
In his first shot at dethroning 185-pound champion Anderson Silva, Sonnen put his foot on the gas for the better part of five rounds until he was caught in the Brazilian's triangle choke. In addition to showing improved submission defense, Sonnen will undoubtedly be looking to dictate the pace of the fight once again in his rematch with Silva at UFC 148 on Saturday.
With all title fights being booked for 25 minutes of action, great conditioning is a must for fighters who have hopes of becoming and remaining UFC champion. Here are the fighters in each of the UFC's eight divisions who have the most in their gas tank.