Isolation: All submission holds presuppose the idea of isolating a limb/neck from the rest of the body in a way that enables you to enact breaking pressure/strangulation. The idea is to get a big percentage of your body to fight against a small percentage of your opponents body. It's difficult to overcome the unified strength of an opponents entire body – but much easier to overcome the divided strength of a single limb that is being held apart from the rest of the body.
