There is no evidence in the scientific literature that stretching prevents injuries, but it can help you to be stronger and faster. Longer muscles can exert a greater torque on joints to help you cycle and run faster, jump higher, throw further and lift heavier. Muscles and tendons tear when the force on them is greater than their inherent strength. Strength training, but not stretching, strengthens muscles. When you exercise against resistance, your muscles become larger and stronger and are less likely to tear.