I've read that it is dangerous to do static stetching without warming up first.
Since the elliptical is pretty low impact for me, I usually just jump right into it. In fact, I'll frequently use the ellipitcal as a dynamic warmup for other exercise--weight lifting and/or the TM. But I would never get on the TM cold; I have enough injuries already. So if I'm not already warmed up, I always start at a warm-up pace for three to five min before ramping up my speed on the TM. But then I generally run intervals starting at 7.8 mph and increasing to 8.8 mph--going from 0 to 7.8 is not smart!
FYI, here are a couple of entries on this topic from a blog I read:
Not that I follow any of his advice.
I hate warm-ups and stretching because it always feels like a waste of time. It's all I can do to make myself stretch at the end of a workout.