Stretching loosens the muscles and tendons, which relieves muscle fatigue and increases blood flow to the muscle and makes possible for you to work out for a longer period. Stretching improves athletic performance in some activities and decreases the risk of activity-based injuries. Stretching must not be considered a warm-up so be careful and do not stretch cold muscles. Consider a 10 minute warm-up before stretching if you want to get the best performance in your exercise. Also a stretching is recommended after you exercise.