As Sean says, you can find hundreds of books on stretching on Amazon, but only three books on muscle activation. I am not sure if I have any books primarily trying to teach muscle activation (I do have 2 cds), although looking at some of these moves, I think it just might be what you are calling what you do. Do not confuse these movements with Muscle Activation Technique. I did go through many sessions of MAT and it was costly and only benefited me in the short term. MAT involves testing, small movements, and retesting. The movements are done while lying down and you need a practitioner to help you. I think Sean's moves are more about loading and firing your muscles. You might find this an inexpensive way to think about your muscles in a new way, help out some weak muscles or movement problems, or deal with imbalances.