Swift as the wind on your feet, you run faster than most and are adept at moving around. Not only are you an incredible sprinter, you are able to keep the pace for far longer than most. Use this trait whenever you need to move fast, such as trying to catch up to someone or fleeing something. You also use this trait to stave of shock when sprinting, so use this trait for the Athletics check.
In combat, you can move faster and longer than others. A decent guide for the Keeper is that you can run an extra meter per step of this trait.