In grappling, an armlock is a single or double joint lock that hyperextends, hyperflexes or hyperrotates the elbow joint and/or shoulder joint. An armlock that hyperflexes or hyperrotates the shoulder joint is referred to as a shoulder lock, and an armlock that hyperextends the elbow joint is called an armbar. Depending on the joint flexibility and integrity of a person, armlocks that hyperrotate the shoulder joint can also hyperrotate the elbow joint, and vice versa.
Obtaining an armlock requires effective use of full-body leverage in order to initiate and secure a lock on the targeted arm, while preventing the opponent from escaping the lock. Therefore, armlocks are usually more easily performed on the ground, from positions such as the mount, side mount, or guard. Armlocks are more difficult to perform when both combatants are standing up, though the stand-up variants are a focus in certain systems such as Chin Na. A failed armlock can sometimes result in the opponent escaping and obtaining a dominant position.
Armlocks are considered less dangerous techniques in combat sports allowing joint locks, and are the most common joint locks used as submission holds. In sparring or training, armlocks are generally done in a slow and controlled manner, so that the opponent can submit before any damage is inflicted. In self-defense application, or when applied improperly or with excessive force, armlocks can cause muscle, tendon and ligament damage, even dislocation, or bone fractures.
The Armbar, also sometimes The English word "bar" is used here to signify the opponent's extended arm, while the Japanese word "juji" refers to the armbar's visual resemblance to the number 10 as written in Kanji. The word juji is also found in "juujika", meaning a cross. In general, the practitioner secures an arm at the wrist of the opponent, trapping it by squeezing the knees together. The attacker's legs end up across the opponent's chest, with the arm held between the thighs, with the elbow pointing against the thigh or hips. By holding the opponent's wrist to the attacker's chest with the pinky finger on the sternum and the thumb facing up (arm semi supinated or semi pronated), the practitioner can easily extend the opponent's arm and hyperextend the opponent's elbow. The attacker can further increase the pressure on the elbow joint by arching their hips against the elbow. This technique is used in various grappling martial arts, including but not limited to; Brazilian jiu-jitsu, Catch wrestling, Judo, Jujutsu, Sambo, Shoot wrestling, and is one of the most common ways to win a match in mixed martial arts competition.
The flying armbar is a version of the juji-gatame that is performed from a stand-up position. Without a gi, it is typically applied when the opponent has a collar tie. By tightly holding the opponent's neck and arm, the practitioner places one of their shins against the opponents midsection, and leans up on the opponent; at the same time, the attacker swings the leg on the same side as the opponent's collar tie over the opponents head, into the typical juji-gatame position. (With a gi, it can be performed without needing to hold the neck.) If improperly performed, this technique will cause the opponent to escape the hold and gain an advantageous position, even the option of slamming the attacker to the ground. The flying armbar is considered to be one of the most visually spectacular joint locks, but it is uncommon because of the risk of losing position.
The Helicopter armbar is a little different version of the armbar, which is also used by Wrestling and Jiu Jitsu. When the attacker stands in front of the opponent, he grabs both of his arms and falls backwards, causing the opponent to lean forward. Then the attacker puts his feet on the opponent's stomach or hips and lifts him up with his feet. The attacker will drop the opponent beside him, and perform the armbar.
The sankaku-gatame or "triangular armlock" is a juji-gatame performed from the sankaku position. Originating from Judo it is normally used when the shime (strangle) is not working. It's an effective competition technique due to the fact that the opponent's arm became exposed while defending the sankaku-jime and their attention is focused in stopping the strangle.