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 from a dominant grappling position on the ground 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. Armlocks not hyperextending the elbow joint are in Judo and some other budo arts called ude-garami ("arm entanglement"). Ude-garami is a legal technique in Judo competitions, even though depending on how it is applied, it may also affect the shoulder joint, or often primarily the shoulder joint.

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.

Click here to see a video of the Juji Gatame or Armbar technique used in Judo.

Click here to see another video of the Armbar technique.

Source: Wikipedia (www.wikipedia.org)