Let's look at some of the fighters who ruined their own careers with actions outside of the cage. 1.) Cain Velasquez: I have Cain at the top because he was most likely the fighter who ruined perhaps one of the greatest potential MMA legacies and is still considered the HW GOAT by many. If he had stayed healthy I'm sure he could still even be UFC HW champion. How did Cain ruin sabotage his career? By not training properly. Cain in the 21st Century was performing weight lifting techniques that high school students would know were being done improperly. Because of this Cain has had 8 surgeries, 4 of which are for his knees. (Two meniscus surgeries, one MCL surgery on my right knee, taking cartilage out of my left elbow, both shoulder I've had torn labrums that needed repairing, and back surgery and a 5th on one of his knees.) This gif of Cain improperly doing knee extensions with huge weight and as fast as possible still makes me cringe. Everyone knows this isn't the proper way to do knee extensions and will most likely lead to injuries..hello Cain. With Cain's knee buckling during his recent fight with Ngannou it's safe to say that he will never hold a belt again which is a tragedy. What a stupid way to derail a potentially legendary career. I'm no fan of Cain, I always believed he was over-rated but I will admit that if he had stayed healthy he could have been one of the greatest of all time not just HW GOAT. I will say I always thought DC would beat him though, more punching power, better wrestling, and better chin. Would have been a great fight. 2.) Diaz Brothers: These two most likely would never be champions but they could have put on many entertaining fights and made themselves a lot of money. What ruined their careers was putting marijuana usage over fighting and over-rating their value. If they played ball they could have had a lot more fights. I wasn't a fan of the Diaz's initially but have warmed to them and do enjoy watching them fight. 3.) Jon Jones: PED use and recreational drug use hasn't helped his career but because of the UFC hasn't torpedo'd it fully either. It definitely tarnished his legacy and Jon better realize the UFC will only cover for him while he's valuable to them, once he no longer is, his antics won't be tolerated or protected. Numerous car accidents and police incidents don't help either. 4.) BJ Penn: I'll put BJ for what he didn't do outside of the cage rather than what he did. In his prime Penn relied on his natural ability and skills and did not train enough. I remember hearing about other fighters warming up for their fights and BJ was on a couch eating a burrito before his fight. BJ is still considered one of the best LW fighters of all time but he could have been great if he really applied himself. Reminds me of Tour de France rider Jan Ulrich who was very similar to Penn and would come into race time approximately 40lbs. over weight. He also partied very hard off season with alcohol and drugs it is said, similar to Penn. What was said about Jan was "Superstar talent and bargain basement motivation.". Same could have been said for BJ. MMA Fighters who torpedo'd their own careers without outside the cage actions?