The value of "the warm up" is significantly under-rated by most people. It's usually skipped or done half-assed in a 5 seconds or less kind of way. As I've gotten older, I've started to feel that it takes me longer and longer to warm up. Or maybe I've always needed about 15-30 minutes to get myself going, truly in the sense that I feel like I can go at full speed and not have to worry about it.
For example, when I first started to play golf, I always felt like my first 9 holes were a warm up and the back 9 nine was always much better. I felt like I could've played better if I just had another 9 holes to play. But, then I realized that if I spent 15-20 minutes prior to playing warming up on the driving range, that would give me the same effects as if I had just shot a crappy first 9!
Depending on what you want your body to do, the warm up is going to vary and will often match the movements that you will be soon performing. In my case, I am working on a plyometric program filled with Running, Jumping and Skipping. Here's a dynamic warm up that can be done anywhere from 2-4 sets of 30ft-50ft. Work through one of each until the set is finished and start back from the top.
o While skipping forward, emphasize speed of movement and vigorous arm action with both elbows bent at 90° flexion.
o While moving forward, rapidly kick heels toward butt while emphasizing speed of movement and quick feet
o While skipping forward, emphasize the height of each skip, high knee lift, and vigorous arm action with both elbows bent at 90° flexion.
Lean to Sprint
o From a standing position with feet close together, lean forward and sprint to 5 yards and accelerate through 10 yards.