DESCRIPTION
Okay let's begin with the armlocks. When you try to sobmit an opponent, basically what you're trying to achieve is to force the articulations or joints of the body, to make them hyperexetnd and move beyond their normal range of motion. In an extreme application it can cause dislocation, fracture and severe injuries, but our goal this time is just causing pain to hold the opponent and making him tap. That's also very useful in self defense.
The armlocks try to force one or more of the three joints in it: the wrist, the elbow and the shoulder.
This time, I would like to talk about the juu-ji gatame or "armbar", one of the most popular armlocks. The way of applying it varies since it depends of the starting position of the attacker. In either a sparring, a combat or in self defense, you're not always going to get the opponent where you want him to be, so you have to be resorceful and see and opening from each one.
As you see in the picture, this is the final position we're trying to achieve. Keep in mind that as I said, it all depends from which position you start, and the movements the opponent does, and it could be a totally diferent end position and still be an armbar like in the picture below.
An armbar (sometimes called a straight armbar) is a joint lock which hyperextends the elbow joint. It is typically applied by placing the opponent's extended arm at the elbow over a fulcrum such as an arm, leg or hip, and controlling the opponent's body while leveraging the arm over the fulcrum
The most common and useful variation of the armbar is the so called "juu-ji gatame" which comes from Judo.
APPLICATION
The juji-gatame (十字固, "cross armlock" or technically referred to as ude-hishigi-juji-gatame; in professional wrestling the technique is referred to a "cross armbreaker" or "crucifix armbar") can be performed on either one of the opponent's arms. In general, the attacker grabs the wrist of the targeted arm of the opponent, holding and securing it by squeezing it between the thighs of the attacker. 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, the attacker can extend the opponent's arm and hyperextend the opponent's elbow, creating pressure in the elbow joint. The attacker can further increase the pressure by arching his or her hips against the elbow. This is extremely effective against unknowledgeable opponents.
MEDIA
Here's a very good explanation of how to perform an armbar from a guard position
In this video we can see an armbar from a back mount position
And the most common mount position
And here form the north-south position
Here it is from the side control position
