Dr. Laskowski: The lying hamstring curl is an exercise you can do with a weight machine to work the muscle in the back of the thigh. As the name implies, the lying hamstring curl targets the hamstring muscle, located here. Strong hamstring muscles help protect the knee from injury.

Nicole Campbell: To do a lying hamstring curl with a weight machine, start by lying on your stomach on the weight bench. Position the pad just above your ankles. Slowly bend your knees, pulling your feet toward your buttocks. Only go as far as you can without feeling your pelvis or spine move. Then slowly return to the starting position. You'll feel tension in the back of your thighs.

When you're doing a lying hamstring curl, use the handgrip for support only. Let your leg muscles do most of the work. Do not pull with your arms or arch your neck or lower back.

For most people, one set of 12 to 15 repetitions is adequate.

Remember, for best results, don't pull with your arms or arch your neck or low back, and keep your movements smooth and controlled.