The hamstring refers to the three muscles that run along the backside of the thigh. They are what enables the leg to bend at the knee. When one or more of these muscles become stretched too far, though, a hamstring strain occurs. Hamstring strains can cause mild to severe pain in the back of the thigh and lower buttock, tenderness, and bruising. As is the case for most strains, people report hearing a popping sound and feeling severe pain as the injury happens. Those individuals who play a sport that requires sudden starts and stops as well as a lot of running and jumping are at a higher risk for developing a hamstring strain. This injury is also common when the quadriceps (the muscles in the front of the thigh) are stronger than the hamstring and in children or teens going through growth spurts. Properly warming up and stretching before a workout or game is a great way to prevent a hamstring injury from occurring. Typical treatment for a hamstring strain includes RICE: rest, ice, compression, and elevation. Taking over-the-counter anti-inflammatory medication such as ibuprofen and performing gentle hamstring stretching and strengthening exercises—as pain permits—may also be beneficial. If the hamstring tears, surgery to repair and reattach the muscle may be necessary.