When I run I can usually aproximately guess my pace within about 20-30 seconds based on my effort level. I've read that elite runners know their pace almost down to the second...how do they do this? Is it just from experience, or are there some methods you can use during workouts to learn how to do this? I don't expect to get it down so close, but even within 10 seconds would be good. I'm typically much more accurate on roads/flat terrain than on hilly trails.