Originally Posted by supineAnimation
Yeah, because medicine ball and resistance band exercises will turn you into Conan. Throwing medicine balls using the same mechanics you use to swing your forehand will improve your ability to use the kinetic sequence of legs-hips-core and will strengthen those muscle groups in an exactly the way you use them in your swing.
Never understood the fear of lifting when people want to swing faster or improve racket head speed. I don't think most people understand that a lifting routine is not going to automatically turn you into a bodybuilder, it actually takes a lot more effort to do that.
Most recreational players are for lack of a better word, soft. So incorporating a good lifting program to strengthen up core muscles, and legs (in other words strengthening the parts of the kinetic chain) will help give you racket head speed if you make sure that you're doing it right.
Never ever underestimate flexibility, even if you're doing a very mildly intensive program, always do plenty of stretching so that you retain your current flexibility and possibly improve it, otherwise despite your added strength your swing might slow down.