So Frank Mir breaks bones with toe holds, armbars, and now with the dreaded kimura; one of the most agonising and potentially career-ending submission holds in the UFC. Armoured by heft and monumental pressure, this complex grapple forces the fighter trapped into a dizzying state of anguish. The attacker grabs a double wristlock and cranks behind the opponent's back. The hold puts an incredible amount of stress on the shoulder, which can very easily cause horrible damage. This lethal submission has seen many victims across a wealth of MMA promotions (a particularly brutal encounter happened at Pride 10 when Kazushi Sakuraba broke Renzo Gracie's arm, and then Gracie was still insistent to fight on!), but the worst kimura inside the UFC Octagon was certainly Mir's blood-curdling effort on Antonio Rodrigo Nogueira, when he broke the arm in truly horrendous fashion. So bad was the break that it is surprising how "Big Nog" maintained such a prosperous career afterwards. He retired from professional MMA a number of months ago.