Aknockout (abbreviated toKO orK.O.) is a fight-ending, winning criterion in severalfull-contactcombat sports, such asboxing,kickboxing,Muay Thai,mixed martial arts,karate, some forms oftaekwondo and other sports involvingstriking, as well asfighting-basedvideo games. A full knockout is considered any legal strike or combination thereof that renders an opponent unable to continue fighting.
The term is often associated with a sudden traumaticloss of consciousness caused by a physical blow. Single powerful blows to the head (particularly the jawline and temple) can produce acerebral concussion or acarotid sinus reflex withsyncope and cause a sudden, dramatic KO. Body blows, particularly theliver punch, can cause progressive, debilitating pain that can also result in a KO.
In boxing and kickboxing, a knockout is usually awarded when one participant falls to the canvas and is unable to rise to their feet within a specified period of time, typically because of exhaustion, pain, disorientation, orunconsciousness. For example, if a boxer is knocked down and is unable to continue the fight within a ten-second count, they are counted as having been knocked out and their opponent is awarded the KO victory.
In mixed martial arts (MMA) competitions, no time count is given after a knockdown, as the sport allowssubmission grappling as well asground and pound. If a fighter loses consciousness ("goes limp") as a result of legal strikes, it is declared a KO.[1] Even if the fighter loses consciousness for a brief moment and wakes up again to continue to fight, the fight is stopped and a KO is declared.[2] As many MMA fights can take place on the mat rather than standing, it is possible to score a KO via ground and pound, a common victory forgrapplers.
Infighting games such asStreet Fighter andTekken, a player scores a knockout by fully depleting the opponent'shealth bar, with the victor being awarded the round. The player who wins the most rounds, either by scoring the most knockouts or by having more vitality remaining when time expires during each round, wins the match. This differs from combat sports in reality, where a knockout ends the match immediately. However, some fighting games aim for a more realistic experience, with titles likeFight Night adhering to the rules of professional boxing, although technically they are classified assports games, and share many of the same features asNFL andNBA video games.
Atechnical knockout (TKO orT.K.O.),stoppage, orreferee stopped contest (RSC) is declared when the referee decides during a round that a fighter cannot safely continue the match for any reason. Certain sanctioning bodies also allow the official attending physician at ringside to stop the fight as well. In amateur boxing, and in many regions professionally, including championship fights sanctioned by theWorld Boxing Association (WBA), a TKO is declared when a fighter is knocked down three times in one round (called an "automatic knockout" in WBA rules).[3] Furthermore, in amateur boxing, a boxer automatically wins by TKO if his opponent is knocked down four times in an entire match.[4][5]
In MMA bouts, the referee may declare a TKO if a fighter cannot intelligently defend themselves while being repeatedly struck.[1]
Adouble knockout, both in real-lifecombat sports and infighting-basedvideo games, occurs when both fighters trade blows and knock each other out simultaneously and are both unable to continue fighting.
In amateur boxing, a double knockout result is determined based on the round of competition. In all contestsexcept the final, both fighters are declared to have lost the contest and are eliminated. In the final, where there must be a winner, the contest ends as if the bell sounded at the end of the final round, and the round is scored, with the winner determined by points. However, if both boxers are downed, both rise up, but one has reached the limit of knockdowns, the winning boxer is the one who has not reached the three/four knockdown limit.[5]
Little is known as to what exactly causes one to be knocked unconscious, but many agree it is related to trauma to thebrain stem. This usually happens when the head rotates sharply, often as a result of a strike. There are three general manifestations of such trauma:
A basic principle of boxing and other combat sports is to defend against this vulnerability by keeping both hands raised about the face and the chin tucked in. This may still be ineffective if the opponent punches effectively to thesolar plexus.
A fighter who becomes unconscious from astrike with sufficientknockout power is referred to as having beenknocked out orKO'd (kay-ohd). Losing balance without losing consciousness is referred to as beingknocked down ("down but not out"). Repeated blows to the head, regardless of whether they cause loss of consciousness, may in severe cases causestrokes orparalysis in the immediacy,[6] and over time have been linked to permanentneurodegenerative diseases such aschronic traumatic encephalopathy ("punch-drunk syndrome"). Because of this, many physicians advise against sports involving knockouts.[7]
Aknockdown occurs when a fighter touches the floor of the ring with any part of the body other than the feet following a hit, but is able to rise back up and continue fighting. The term is also used if the fighter is hanging on to the ropes, caught between the ropes, or is hanging over the ropes and is unable to fall to the floor and cannot protect himself. A knockdown triggersa count by the referee (normally to 10); if the fighter fails the count, then the fight is ended as a KO.[8]
Aflash knockdown is a knockdown in which the fighter hits the canvas but is not noticeably hurt or affected.[8]
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