About six weeks ago I decided to get my butt back in shape. I'm not a Budda Boy by any means, but my cardio sucked, and my weight training was non-existent. I'm slowly building back into my cardio, but the hardest thing was getting back into the swing of lifting.
I lift 3 to 4 times a week focusing on different muscle groups each day. Lately it's only been about 3 days because I just can't force myself to work legs (squats, leg press, curls, etc..). Since I'm trying to get back into cardio shape, my legs kinda reject any unwanted excercise. Anyway, I've been doing a mixture of certain things just to get an idea of what will work best. I do high weight (at least for me it is) for 6-8 reps. I try to hit the muscle groups at as many different angles as possible. Towards the end of my workout, I'll switch to a lower amount of weight and do as many reps as possible which by that point is only about 10, by that point I've reached muscle failure. I've found that if I do this last part I work the muscle group through full extension and contraction which is very important. You don't want to work short range with heavy weights, although you may gain mass alot faster you'll also lose flexibility, plus you increase your chances for an injury (i.e. rotator cuff, knee, although less likely... even a hip injury).
Lately I've also been working with one of those TKD resistance bands. You know the one where you velcro one end to your foot and the other to a stationary object, then you do kicks. I've been using it with a variety of kicking and punching drills. Your only supposed to have resistance in the last 3-4 inches of the movement. I've already noticed an increase in my kicking and punching speed. I can't tell if my power has increased (the heavy bag doesn't say "owwwww"). While I realize that working on kicks is about as useful as learning to use the sai's in a real fight (don't see to many of those just laying around on the streets anymore), I figure if I can effortlessly kick someone in the head, then I shouldn't have a problem kicking to the inside/outside of the thigh or knee.
Anyway, that last part was a little off subject. While I'm no expert I would agree with everyone and say that appropriate stretching is of paramount importance. Whatever workout regimen you decide to go with, make sure that you work full range of motion and that your working both sides of the muscle grouping (i.e. quads/hamstrings). Also you can do abduction and adduction (notice the "B" in the first one) excercises for the legs. I can't tell you how many friends I've had blow their knees because they weren't working the little mucsles to the inside of their thighs (You know the excercise that looks like your in a birthing chair and squeezing your legs together..... it may look dumb as hell, but try it and see how you feel afterwords).
Well, I could go on forever but I'll leave it at that. Hope this was somewhat helpful. Good luck.