A knockout (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. 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 traumatic loss of consciousness caused by a physical blow. Single powerful blows to the head (particularly the jawline and temple) can produce a cerebral concussion or a carotid sinus reflex with syncope and cause a sudden, dramatic KO. Body blows, particularly the liver punch, can cause progressive, debilitating pain that can also result in a KO.
In boxing, kickboxing, etc. 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, or unconsciousness. 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 allows submission grappling as well as ground and pound. If a fighter loses consciousness ("goes limp") as a result of legal strikes it is declared a KO.〔http://www.ufc.com/discover/sport/rules-and-regulations#17〕 Even if the fighter lost consciousness for a brief moment and woken up again to continue to fight, the fight is stopped and declared a KO.〔http://mixedmartialarts.com/mma-news/341856/Herb-Dean-The-fight-is-over-when-hes-unconscious〕 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 for grapplers.
A technical knockout (TKO or T.K.O.) is declared when the referee or official ring physician decide that a fighter cannot safely continue the match. In boxing, this refers to any situation when the referee, cornerman, physician, or fighter stops the fight any time when there is no ten count, most notably when a fighter has been knocked down three times in one round, which ends the match in most regions.〔Sugar, Bert. (Boxing ). ''www.owingsmillsboxingclub.com''. URL last accessed March 4, 2006.〕 British records refer to TKOs as either "retired", if the fighter refuses to continue, or "referee stopped fight" (RSF). In amateur boxing, a knockout is scored as "referee stopped contest" (RSC). A technical knockout ("outclassed") can also be declared if a fighter is behind by 15 points in a bout. In MMA the referee declares TKO when a fighter is not intelligently defending himself while being repeatedly struck. 〔
Types of technical knockouts:
* Doctor's stoppage/injury: The fighter has suffered an injury and cannot continue the match safely. In some cases, an accidental injury (such as clash of heads), once a match becomes official (more than half the distance, or four rounds, in most jurisdictions) is grounds for the fight being declared finished, and valid decision is made.
* Corner stoppage: The fighter is being completely battered, to the point where it is too dangerous for him to continue. In some cases, the fighter may have been injured. The fighter's corner decides to surrender on the fighter's behalf to prevent unnecessary damage or potential injury. (This is also known as "throwing in the towel".)
* Stoppage because of strikes: The fighter is overwhelmed by strikes (blows) and cannot intelligently defend himself. The referee intervenes to avoid unnecessary damage or potential injury.
* Multiple knockdowns: The fighter is knocked down three times during a single round (common rule in most boxing and kickboxing contests), or in some sanctioning bodies, four in a fight. Does not apply to MMA.
A technical knockout goes down as a knockout in the boxer's record. But as a TKO in an MMA fighter's record.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』