Armlock

An armlock in grappling is a single or double joint lock that hyperextends, hyperflexes or hyperrotates the elbow joint or shoulder joint. An armpit lock can be useful; it will immobilize an opponent and pin them on the ground. An armlock that hyperextends the elbow is known as an armbar, and it includes the traditional armbar (pressing the elbow against the thigh or hips), the shoulder triangle armbar (where a figure-four is locked with the legs), and the shotgun armbar (where the opponent's wrist is placed in the armpit, using the forearm as a fulcrum). An armlock that hyper-rotates the arm is known as an armcoil, and includes the Americana, kimura, and omaplata. Depending on the joint flexibility of a person, armcoils can either hyperrotate only the shoulder joint, only the elbow joint, or both the elbow joint and shoulder joint.

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, performing an armlock is less problematic on the ground, from positions such as the mount, side control, 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.

Armlocks, considered less dangerous techniques in combat sports allowing joint locks, are the most common joint locks used as submission holds. In training, the method of executing an armlock is generally slow and controlled to give the opponent time to submit prior to any infliction of injury. However, in self-defense applications, or when applied improperly or with excessive force, armlocks can cause muscle, tendon and ligament damage, even dislocation, or bone fractures.

The jūji-gatame (十字固め, rendered as "Ude-Hishigi-Juji-Gatame"), which translates to "cross pin" or "cross hold down" also sometimes used interchangeably with the terms armbar, cross armbar or straight armbar, is a Jujutsu, and thus a Judo, technique also widely used in other grappling martial arts such as Brazilian jiu-jitsu (BJJ). The English word "bar" is used here to signify the opponent's extended arm, while the Japanese word "jūji" (十字) refers to the armbar's visual resemblance to the number 10 as written in kanji, 十. The word jūji is also found in "jūjika" (十字架), meaning a cross. In general, the practitioner secures an arm at the wrist of the opponent, trapping it by squeezing the knees together. To initiate the submission one of the legs will be across the chest of the opponent, the second leg's calf will cross face the opponent, with the hips tight into the armpit, 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 his hips against the elbow. Alternatively, gripping the opponent's wrist and forearm, while pushing the hips closer to the opponent's elbow and crossing one leg to make a leg triangle around and press down the opponent's humerus/scapula/biceps and triceps/shoulder, could make the hold more secure while additionally allowing the practitioner to deliver strikes to the opponent's head and neck with the non-crossed leg. This technique is used in various grappling martial arts, including but not limited to Brazilian jiu-jitsu, catch wrestling, judo, jujutsu, Sambo, and shoot wrestling, and is reportedly at least 200 years old.

The flying armbar or tobi-jūji-gatame (飛び十字固め) is a version of the jūji-gatame that is performed from a stand-up position. Without a gi, it is typically applied when the opponent has a collar tie and arm control. By tightly holding the opponent's neck and arm, the practitioner places one of his shins against the opponent's 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 opponent's head, into the typical jūji-gatame position. A slight modification of this maneuver can also be made. Instead of initiating the move by placing the shin against the opponent's midsection, the lower leg can be directed through the space between the arm and trunk of the opponent with the knee generally placed close to the opponent's armpit. The advantage of this modification is that the attacking practitioner's hips more closely engage with the defender's shoulders, making the forthcoming armbar submission easier to accomplish. However, the disadvantage of this modification is that the associated risk of injury is increased due to the attacker's increased height above the ground and near-vertical upside-down angle to the ground. (With a gi, it can be performed without needing to hold the neck.) If improperly performed, this technique can allow the opponent to escape, and gain an advantageous position. The flying armbar is considered to be one of the most visually spectacular joint locks, but it is uncommon because of the associated risk of falling into a poor position.

The helicopter armbar is a slightly different version of the armbar, a combination of an armbar and tomoe nage, which is also used by wrestling, Judo and BJJ. 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. While securing one of the opponents arms, the attacker will drop one foot (Same side as the secured arm). This will cause the opponent to twist and fall, landing with the secured arm extended by the attacker.

The sankaku-gatame (三角固め) or triangle armlock is a jūji-gatame performed from the sankaku position. It is normally used when the shime (strangle) is not working. It is an effective competition technique because the opponent's arm became exposed while defending the sankaku-jime and their attention is focused in stopping the strangle.

The "shoulder lock" is a technique used as a method of upper body restraint. It should not be confused with a choke because the lock does not block or interfere with the flow of air or oxygen to the brain. The application is executed by applying pressure between the radial bone and shoulder.