The hamstring muscles that help you extend your leg straight back and bend your knee, run down the back of the thigh. They are a common place for injury, especially among athletes who participate in sports that require sprinting such as track, soccer and basketball, but can also affect runners and skaters.
A hamstring injury can be a pull or strain, partial or complete tear and occur most often in the thick part of the muscle or where the muscle fibers join the tendon fibers. In the most severe hamstring injuries, the tendon tears completely away from the bone, and may even pull a piece of the bone away with it. This can happen when there is a large sudden overload on the muscle.
Most hamstring injuries heal with nonsurgical treatment and physical therapy after the pain and swelling have settled down. However, the more severe injuries require surgery to repair a tear.