Running

I've only recently bothered to do any sort of separate warm-up before running, but not always. If I bother at all it's usually just because I'm waiting for the Garmin to fire up. It'll mainly target warming up the hamstrings and quads, some dynamic stretching, some lunges, etc. But often I'll just head out and start with whatever slow pace feels comfortable and speed up without thinking about it, as the muscles loosen up and I get into a rhythm. The first mile will often be around a min/mile slower than the average for the run.

For a race or interval session I'll warm up for minimum two miles, more like three (less for HM, even less for marathon), not just to get the legs loosened up, but to get the heart and lungs going as well. An interval session warm-up would be three miles easy pace plus strides, race warm-up more likely three miles progressive, getting close to race pace, plus strides, so that the first part of the race isn't too much of a shock.