The more flexible you are, the faster you can go, with less effort. Flexibility, or the lack of it, is one of the most limiting factors for achieving your full potential for speed. The upside of having supple or flexible muscles is huge: the more flexible you are, the more your muscles will work with you, and not against you, when you most need them. One of the keys to flexibility is consistent and targeted stretching, in that it assists with flexibility and helps decrease aches and pains that can limit your mileage. Three main areas on which to focus your stretching are the illiotibial (IT) band, the quads, and the hip flexors. Most experts agree that while gentle stretching as part of a warm-up is important, the greatest benefit will come from post-work out stretching. It is equally important that you target your stretching to focus on the muscles used in the workout.