How to Do Seated Leg Curl: Muscles Worked & Proper Form

Seated Leg Curl exercise technique

Muscles Worked in Seated Leg Curls

Muscles worked by seated leg curl

Primary muscles worked:

How to Do Seated Leg Curls

  1. Adjust the machine so that you are correctly positioned. Your knees should be in line with the machine’s joint.
  2. Push the weight down by bending your knees as far as possible.
  3. Slowly let the weight back again.

Which Muscles Do the Seated Leg Curl Work?

The seated leg curl is an isolation exercise that works your hamstrings and is one of the best hamstring exercises you can do.

Muscles worked by seated leg curl

A recent study showed that the hamstrings grew 55% more from doing seated leg curls compared to lying leg curls.1

This difference in muscle growth can probably be explained by the fact that seated leg curls work your hamstrings at a longer muscle length than the lying leg curl since your hip is flexed more, and three out of four hamstrings head cross over your hip joint.

Benefits of the Seated Leg Curl

  • Isolates the hamstrings effectively. The seated leg curl lets you train the hamstrings effectively without involving other muscle groups. This helps you focus 100% on the hamstrings without other aspects such as grip strength, balance, etc interfering.
  • Improved athletic performance. Stronger hamstrings can help to increase power, speed, and agility in various sports and physical activities.
  • Injury prevention. A strong and flexible hamstring can help to reduce the risk of hamstring strains, and by avoiding injury, you’ll be able to keep working out and get even bigger and stronger.

Seated Leg Curl: Proper Form & Technique

seated leg curl starting position
Starting position
seated leg curl bottom position
Bottom position


Take your time to adjust the machine so that it fits your body. The most important part here is to make sure that your knees align with the machine’s joint. Otherwise, the movement pattern will be off and might hurt. Adjust the back pad as well, so that you can keep your back flat against it.


When you’ve made sure that you have a good position in the machine, brace your core and start the movement by curling your legs as far as possible. Keep the motion slow and controlled to maximize the muscle engagement.

Common Mistakes in the Seated Leg Curl

  • Not adjusting the machine correctly. By not adjusting the leg pad and seat height to your body, the exercise will be very hard to perform, and it can lead to an ineffective and possibly painful exercise.
  • Adding too much weight. If you add more weight than you can control, it’s easy to start relying on the momentum and swinging the weight. Besides fooling yourself, and making the exercise less effective, this can cause harm to the machine as well. Lower the weight, and keep the movement controlled and slow.

Seated Leg Curl Alternatives & Variations

  1. Lying Leg Curl
  2. Romanian Deadlift
  3. Nordic Hamstring Curl

1. Lying Leg Curl

As mentioned earlier, a study showed that the seated leg curl might grow your hamstrings better than the lying leg curl.

However, according to said study, the sartorius muscle grew better from training lying leg curls, and gracilis and biceps femoris short head grew equally well from both. Therefore, you might benefit from training both seated and lying leg curls for optimal hamstring growth.

2. Romanian Deadlift

The Romanian deadlift is a barbell hamstring exercise, and a good complement to the seated leg curl. The seated leg curl works your hamstrings in knee flexion, while the Romanian deadlift works the other function of hamstrings – the hip extension. By doing both of them, you target all the functions of the hamstrings.

You can perform the Romanian deadlift with a barbell or with a pair of dumbbells.

3. Nordic Hamstring Curl

While writing about hamstring training, it’s hard not to mention the Nordic hamstring curl. The Nordic hamstring exercise is a great exercise if:

  1. You are able to do it at all, or …
  2. You are training to reduce the risk of a hamstring strain from sports like sprinting, soccer, or football.

However, most people cannot do the concentric phase of the Nordic hamstring curl, especially not for multiple reps. Therefore, it might not be a good alternative for most lifters. But if you’re capable of doing it for several reps, and like the exercise – feel free to add it to your routine!

How Many Sets and Reps Should You Do in the Seated Leg Curl

The number of reps that you should train varies depending on your goals, this goes for all exercises.

  • For muscle growth, around 6–15 reps per set are something to aim for.
  • For strength, around 3–8 reps per set are good.

There are no clear-cut lines between these two goals, however. Training in the “muscle growth range” will still increase your strength, and training in the “strength range” will still cause your muscles to grow. It’s just a matter of what you are emphasizing.

Read More: How Many Reps to Build Muscle vs. Strength?

Regarding how many sets you should do, that depends more on your training background and your capabilities. How much work are you used to doing, and how much does it take for you to stimulate growth?

It also depends on how many workouts you do per week. You can tolerate (and grow from) a higher training volume if you distribute it over more workouts.

Training Programs & Workouts that Include the Seated Leg Curl

All these, and many more programs and workouts, are available in our workout log app StrengthLog.

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  1. Med Sci Sports Exerc. 2020 Oct 1. Online ahead of print. Greater Hamstrings Muscle Hypertrophy but Similar Damage Protection after Training at Long versus Short Muscle Lengths.