The hamstrings are a group of muscles in the back of your thigh. These muscles include:

• semitendinosus
• semimembranosus
• biceps femoris

These muscles function together to bend your knee and move your thigh back. This helps you walk, run, and jump.

The hamstring curl, also called a leg curl, is an exercise that strengthens the hamstrings. It involves bending your knees and moving your heels toward your butt while the rest of your body stays still.

Typically, the exercise is done on a leg curl machine. But if you don’t have gym equipment or a gym membership, you can do other types of hamstring curls at home.

These variations require nothing more than your body weight or simple equipment.

Hamstring curl benefits

During a hamstring curl, your back thigh muscles work to lift your lower leg. This movement engages your hamstrings and glutes, which makes them stronger.

When you have strong hamstrings, you’re less prone to injury and pain. That’s because strong hamstrings can withstand the impact of exercise and help to stabilize your knees.

Hamstring curls also stretch your quadriceps, which can help relieve quad tightness and back pain.

Things to keep in mind

It’s important to keep your back neutral during hamstring curls. If you arch your lower back, your hamstrings won’t work properly. Your back will do the work instead, which can cause back pain and discomfort.

To avoid arching your back, contract your abs during the exercise. Contracting your abs will help stabilize your spine. Your knees should be the only thing bending during hamstring curls.

It’s also best to move slowly. Sudden, jerking movements can lead to injury, so your movements should be controlled.

Stop doing hamstring curls if you feel pain in your knees, hips, or back. A personal trainer can suggest alternative exercises to safely work your legs.

1. Standing hamstring curl

The standing hamstring curl is a bodyweight exercise that tones your hamstring muscles. It’s an ideal workout for improving balance and leg strength.

To do a standing hamstring curl:

1. Stand with your feet hip-width apart. Place your hands on your waist or on a chair for balance. Shift your weight onto your left leg.
2. Slowly bend your right knee, bringing your heel toward your butt. Keep your thighs parallel.
3. Slowly lower your foot.
4. Complete 12 to 15 reps.
5. Repeat with the other leg.

2. Seated hamstring curl

This exercise is done with a resistance band around your lower legs. Your hamstrings will have to work extra hard to move your heels against resistance.

To do a seated hamstring curl:

1. Tie the ends of a resistance band to a sturdy object, such as an exercise machine or piece of furniture. Sit in front of the band. Place the loop around one of your heels and keep your feet together.
2. Bend your knee to pull your heel back, stopping when you can’t pull any further.
3. Extend your knee to return to starting position.
4. Complete 12 to 15 reps. Then repeat on the other leg.

3. Prone hamstring curl

Like the seated hamstring curl, the prone version adds resistance to your lower legs. This engages your hamstrings when you bend your knees.

To do a prone hamstring curl:

1. Anchor the ends of a resistance band to a sturdy object. Lie down on your stomach with your feet hip-width apart. Place the band around one heel and flex your ankle.
2. Bend your knee to pull your heel toward your butt, keeping your thighs and hips on the mat.
3. Stop when you can’t pull any further. Return to starting position.
4. Complete 12 to 15 reps.

Try using heavier resistance bands as you get stronger.

Alternatively, you can do the prone hamstring curl without a resistance band.

4. Hamstring curl with a ball

The hamstring curl with a ball uses a stability ball to lift your hips and legs off the floor. When bending your knees, your hamstrings will engage to roll the ball toward your body.

To do this type of hamstring curl:

1. Lie on your back. Put your calves and heels on a stability ball. Place your feet hip-width apart and flex your ankles. Set your arms on the floor, palms down.
2. Move your hips upward until your body is straight. Engage your glutes.
3. Slowly lift your hips and bend your knees. Pull your heels toward your buttocks, moving the ball toward your body until the soles of your feet touch the ball.
4. Extend your knees and lower your hips and back to the floor.
5. Complete 12 to 15 reps.

For an added workout, keep one leg raised or cross your arms on your chest.

5. Hamstring curl with a dumbbell

This exercise uses a dumbbell to add resistance between your feet. The extra weight challenges your hamstrings as you lift your lower legs.

Start with a light dumbbell. As you get stronger, you can use a heavier weight.

To do this type of hamstring curl:

1. Lie down on your stomach and fold your arms in front of you. Place a light dumbbell in between your feet.
2. Bend your knees, moving your heels toward your butt.
3. Return to starting position.
4. Complete 12 to 15 reps.

You can also use ankle weights in place of a dumbbell.

The bottom line

The hamstring curl is an excellent exercise for strengthening your back thigh muscles, which can reduce your risk of injury. Just make sure you avoid arching your back in the process.

Talk to your healthcare provider before trying a new workout. If you have a joint condition, or if you’re recovering from an injury, they might recommend safer alternatives.