Relax: Basically this is your strongest defensive style move. Right before a major hit to a joint, relax the joint and you can up the chances of it not being dismembered or fractured.
Hold: This basically "holds" the joint. It can still bend if enough force is applied however. This is the easiest type of joint to fracture/dismember though.
Extend: Completely locks the joint. Basically you can't bend the joint any other way if it is extended.
Contract: Pulls the limbs and body parts attached to that joint inwards to the center of the body. This is normally used to punch and bend your knees and such.
"This is the easiest type of joint to fracture/dismember though."to be fracture or fracture the enemy?