Stretching serves many purposes, first and foremost, aiding in your flexibility and range of motion. While you may have heard that stretching can prevent injury, there is not a lot of data to support this claim. In one older study, a static stretching routine resulted in significantly fewer incidences of muscle/tendon injury and lower back pain than in a control group, but total injury rates were equal.  Whether or not you choose to stretch is highly dependent on the type of physical activity for which you’re preparing. In fact, there is some evidence that it may do more harm than good with high-performance athletes. Additionally, the type of stretching that may be appropriate varies as well. It should also be noted that just because stretching feels good, does not mean that it is necessarily preventing injury or that there is not the possibility of it aggravating an existing injury or even causing an injury.