That's my issue with some of the wrist lock work taught in security courses, JGW. Those guys are not going to get enough repetitions to get all of that down, so they should mostly avoid those locks where resistance leads too easily to destruction. The one shown in the video is a good one, because there's a relatively long continuum of application to that. For instance, the way it's used in the video isn't strictly speaking a lock, because there's no base against which to lock it. He's using it to force the uke's weight back (working beautifully in one of the "grey spaces" I love, combining two techniques found in NGA) for the throw. That same lock can be used for pain compliance and lead (like the video), and if applied further can strain the wrist (unlikely to cause long-term damage) and if applied hard and fast with a base behind it can be turned to destruction. Because there's that middle area where it hurts a lot and causes relatively minor injury (strain) that will reduce the limb's effectiveness, it's a good one for security training. I love his selection of it, and just wish he'd shown it used in restraint, as well, because there's a nice transition to putting the guy on his stomach and using the wrist lock (putting a base behind it) or transitioning to a shoulder lock.
