Mike Tyson was an athlete.
A knockout ( abbreviated to KO or K.O. ) is a fight-ending , winning criterion in several full-contact combat sports , such as boxing , kickboxing , muay thai , mixed martial arts , karate , some forms of taekwondo and other sports involving striking . Michael Gerard Tyson ( [ ˈtaɪsən ] born June 30 , 1966 ) is an American former professional boxer who competed from 1985 to 2005 . Tyson retired from professional boxing in 2006 , after being knocked out in consecutive matches against Danny Williams and Kevin McBride . The World Boxing Association ( WBA ) is the oldest and one of four major organizations which sanction world championship boxing bouts , alongside the IBF , WBC and WBO . The World Boxing Council ( WBC ) is one of four major organizations which sanction world championship boxing bouts , alongside the International Boxing Federation ( IBF ) , World Boxing Association ( WBA ) and World Boxing Organization ( WBO ) .