Leg curl machine

The leg curl machine does a great job of strengthening your hamstring muscles.
Use caution if you have a history of lower back discomfort.

Getting set
Set the ankle pads of the machine so that when you lie on your stomach, the underside of the pads are flush with the tops of your heels. Lie down, rest the side of your face on the support pad, and grasp the handles. Gently flex your feet. Pull your abdominals in and tuck your hips down so your hipbones press into the pad. See photo A.

The exercise
Bend your knees to lift the ankle bar until your calves are perpendicular to the floor. Then slowly straighten your legs. See photo B.

Do’s and don’ts

• DO keep your hipbones pressed against the machine and your abdominals pulled in. You may want to lift your thighs just a hair upward before you bend your knees.
• DO lower your legs back down slowly so the weights you’re lifting don’t slam down against the rest of the stack.
• DON’T — and this is a big don’t — allow your butt to pop off the pad. This puts stress on your lower back and minimizes the work being done by your hamstrings.
• DON’T kick your heels all the way to your butt.

Other options
Other curl machines: Some machines work your hamstrings from a standing or seated position. Others have independent left and right sides so that each leg has to carry its own share of the weight. Still others have a “range limiting” device that allows you to cut off the movement at the top or bottom —a good variation if you’re experiencing any pain while doing this exercise.
Single-leg curl: Lift with both legs, straighten one out of the way, and lower the weight down with one leg only.