In Jiu-Jitsu getting a submission means first you have to secure a dominant position but before you can secure a dominant position you must first win a series of small battles with in whatever position you happen to be fighting from.
In Saturdays Brazilian Jiu-Jitsu ( BJJ ) class we demonstrated this idea for the half guard, specifically the upper body control you need to achieve and maintain before you can work any positional advancement. in order to pass half guard you need to achieve an underhook, this particular arm position allows us to keep the bottom Jiu-Jitsu player stuck which makes it much more difficult to stop our guard pass. Once we pinned the bottom Jiu-Jitsu player to the mat we are then free to clear our legs and move to either side control or mount.
The bottom BJJ player has the same battle, he or she must fight for the underhook to avoid being pinned, achieving the underhook allows the bottom Jiu-Jitsu player to remain mobile which provides a number of oppertunities to improve position. In Saturdays Jiu-Jitsu class we drilled two techniques for the bottom player, how to move to your opponents back and how to sweep when the back take is defended.
In this bjj class all four techniques we covered started from one small detail, getting the underhook. Without that underhook neither Jiu-Jitsu player would have the control required to be efficient with the application of their technique and if you are not conserving energy in a match you will fatigue, and if you fatique first, you will lose.