Elbowing

An elbow strike (commonly referred to as simply an "elbow") is a strike with the point of the elbow, the part of the forearm nearest to the elbow, or the part of the upper arm nearest to the elbow. Elbows can be thrown sideways similarly to a hook, upwards similarly to an uppercut, downwards with the point of the elbow, diagonally or in direct movement and in several other ways like during a jump etc.

Elbowing is a disallowed practice in most combat sports. However, Muay Thai, Pradal serey and several mixed martial arts (MMA) organizations do allow elbowing, or allow elbowing in a specific manner. The mixed martial arts organizations disallowing it usually do so because elbowing the head increases the risk of lacerations in a fight.

While elbows are mostly disallowed in most modern combat sports, they are common in traditional martial arts. There are few traditional martial arts that don't use elbows though it depends on which martial art it is, if the elbows are primary or secondary weapons and also in which manner, what tactics and how often they are used. Some well known and respected traditional martial arts that use elbows are Karate, Taekwondo, Hung Ga, Bajiquan, Wing Chun, Silat and Muay boran.

In Muay Thai, elbow strikes are most often used while in close range but are also employed while jumping toward the opponent, similar to Muay Thai's flying knee. The hardness of the elbow allows for hitting with considerable force, and experienced fighters can easily knock out, cut, or injure their opponent with a well-placed strike. Elbows are generally most effective when used in combination with punches or kicks to allow the fighter to close the distance.

Elbows are also used in mixed martial arts as part of the ground-and-pound fighting tactic. Participants often use elbow strikes in conjunction with punches while in the full guard, half guard, side mount, or full mount in order to knock out or overwhelm the opponent.

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Wikipedia