Originally Posted by boramiNYC
doesn't that passiveness explain alot of straight arm or whippy crazy rhs for the high level tennis?
Well, I guess I should have used the word "dead" instead of "passive" in my earlier post! IMO, you are right in that a lot of the movements are passive in that energy is released rather than created. Thus I would advocate having a loose arm structure in general. However, "passive" does not mean no activity ("dead"). Energy is stored during the eccentric contraction phase in many arm muscles for generating power and spin, and some muscles are very active (especially for control related actions). It is too complex to lend itself to a simplistic analysis or description, IMO. I can imagine and feel what happens, but far be it from me to try to quantify it, or even describe it accurately!