Coach Sonnon can you please give tips on the achilles style straight ankle lock. Also, could you give your opinion on any advantages or disadvantages on figure fouring your arms with is lock.
Keep the "blade" of your forearm aligned perpendicular at maximal pressure.
The forearm is composed of thirds. Use the first third (near the wrist) to apply pressure.
"Rake" the forearm in wratchet-like forearm rotations to keep from over-sensitizing the pain. After a certain period the brain shuts-down the pain produced in the region. Pulsing the pressure keeps the pain fresh and full. (There are some other juicy pain-enhancing mechanisms that this causes as well, but are really only useful text for neurogeeks. Just maintain constant but rotating pressure.)
Figure-4 if you use the laced hand to push his shin down simultaneous to your upward pressure. It requires refinement, since this is a complex (multi-directional) skill, rather than the simple (one dimensional) standard. Practice more.
The first third of your forearm (near the wrist) is the thinnest part. Less surface area to apply the same poundage of force = more Pounds per square inch. Same reason a knife cuts.
My personal preference is to apply it on the side of the leg, where the tissue is the thinnest, and there's also a good deal of bone contact. The pressure generated there is usually enough to get one to extend their ankle, so that you can now induce pain on the achilles tendon, but also add the risk of injury to the ankle via hyperextension, as more experienced players can get used to pain tolerance, but will be smart enough to give up if there's a potential injury involved as well.