Hamstring Spasm

The hamstring muscles are lengthy muscles that cross two joints and contract and expand to perform their functions. The impulses sent to the brain control the contraction and expansion motion of the hamstring muscles. A hamstring muscle spasm occurs when a muscle contracts involuntarily.

Muscle spasms most commonly affect the hamstring muscles, as well as the quadriceps, calves, feet, hands, and abdominal muscles. A muscle spasm might be a minor ache or a severe pain that forces you to stop doing whatever you're doing until the discomfort subsides.