Tennis elbow is the common name for a painful condition affecting the outer part of the elbow.
It can be caused by repeated twisting movements of hand, wrist or forearm, and is most common in people aged 35 to 55.
The hamstring is a group of large, powerful muscles at the back of the thigh which extends the hip joint and flexes the knee.
A hamstring injury is caused by a tear in one of the hamstring muscles. It is usually the result of an overuse of the muscles or trying to move them too fast. If an impact has been taken on the back of the leg however, it is treated as a contusion, rather than a hamstring strain.