Stretching safely exposes your body to the strenuous limits that your sport or activity may introduce. By stretching in advance, it “prepares” the body for meeting those limits as they occur by loosening up the muscles slowly and carefully. Without stretching, if your muscle is forced to endure certain limits (typically very quickly and strongly), it can cause damage to the muscles. Stretching in advance will reduce the risk of injury because the muscle is already “prepared” for that exertion of force.