While resting between runs may make a lot of sense, it is much more difficult to wrap your head around the concept of resting while you run. When you go out for a run, the concept of rest that comes to mind is shutting down, sitting down, and possibly laying down. But any of those options aren’t productive for finishing an endurance event. You can’t just lay down and take a nap every time you get tired. You would never cross the finish line if you did that. Instead, why not rest on the run.