You are talking about Kyusho John? A previous Sensei of mine was extremely knowledgable on this. He had studied with the jujitsu/karate community whilst teaching/training aikido and intergrated what he learn't. He was and still is studying hard to understand where it all fits in. He is from a tournament fighting background so his system is very martial. Trouble is, concentrating on such a difficult/vast subject means a lot of time, and you need all you can get to progress in aikido itself!!!