This is the stuff you do at GPP.  Dynamic Stretching is a stretch performed by moving through a challenging, but comfortable range of motion while performing a movement/exercise.  Dynamic Stretching requires more coordinated effort from the nervous system, musculature and energy pathways, thereby improving performance across all of these.  This makes Dynamic Stretching a more efficient and effective form of improving your functional capacity and range of motion.  By working this type of stretching into your workouts, it develops flexibility you can actually use.