The MMA game giveth, and the MMA game taketh away. This cruel and cold lesson has been learned by far too many in this sport.
There comes a time in any athlete's career where he realizes it's time to hang it up. In team sports, that time is usually preceded by a lack of athleticism, maybe an injury or two.
Unfortunately, in MMA that time tends to be preceded by some vicious knockout or bone-crushing submission loss. Far too many of MMA's legends from "the old guard" have gone down in devastating fashion.
Some of the athletes were at the point where they had to fight to live rather than live to fight. Others simply couldn't accept that time had passed them by. Regardless of how they went out, it was clear that the end came way too late.
The ranking for this list is based on how high the fighters reached in their careers combined with how hard they fell. Also included was the manner in which they left the sport.