Arrichion of Phigalia

In 564 B.C., Arrichion of Phigalia, a Greek pankratiast, caused his own death during the Olympic finals. Held by his unidentified opponent in a stranglehold and unable to free himself, Arrichion kicked his opponent, causing him so much pain that the opponent made the sign of defeat to the umpires, but at the same time breaking Arrichion's neck. Since the opponent had conceded defeat, Arrichion was proclaimed the victor posthumously.