Armbar

The armbar is a submission technique.  This means that (ideally) when you apply the armbar to your partner, they give up voluntarily because they think if you keep going with the technique, their arm will break at the elbow.

The elbow is a hinge joint.  This means that, like a door hinge, the elbow is designed to move in two directions through a limited range of motion.  If you push a door (very hard) too far in one direction, you’re likely to break the door off the hinges.  The same holds true for an elbow.

However if you simply grab someone by the arm and attempt to push the “wrong” way on their elbow, they’re likely to simply step away.  You have to first isolate the arm before you can apply useful pressure on it.  If your partner is able to fight you off with strength, then you probably haven’t isolated the arm correctly.

Isolating the arm usually involves getting an angle on your partner and having a fulcrum right behind their elbow.  In the case of our demo video, the angle is achieved by rotating 90 degrees on the floor and the fulcrum is your own hip.  The whole process is made much more manageable when on the ground because the legs can be involved in the process of isolating the arm (rather than being occupied with keeping you upright).