Leg curl: correct technique, seated or lying and the Nordic curl to prevent injuries
Published on
Seated, the leg curl grew the hamstrings more than lying: 14% versus 9% in 12 weeks. Technique, variations and why the deadlift alone is not enough.
In 2021, Sumiaki Maeo and colleagues at Ritsumeikan University (Japan) trained 20 adults for 12 weeks with a one-leg-versus-the-other design: one leg did seated leg curls and the other lying leg curls. Same relative load, same sets, same frequency. Measured with MRI, the hamstrings grew 14% with the seated curl and 9% with the lying curl.
The difference is at the hip. Seated, the hip is bent and the hamstrings work in a more stretched position. Here is how to do the leg curl, which variation to choose and why it should not be missing even if you already deadlift.
What the leg curl works
The hamstrings are three muscles at the back of the thigh: the semitendinosus, the semimembranosus and the biceps femoris. Three of their four parts cross two joints: they extend the hip and bend the knee. The Romanian deadlift works them from the hip; the leg curl, from the knee. To develop them fully you need both movements. You will find the hip one in the Romanian deadlift guide.
How to do the leg curl step by step
- The set-up. Line your knee up with the machine's pivot and place the roller just above your ankle.
- The position. Seated, with your back supported and your thigh held by the pad; lying, with your hips pressed into the bench.
- The lift. Bend your knee as far as the machine allows, without lifting your hips or your thighs.
- At the top. Squeeze for a moment.
- The descent. Controlled, over 2-3 seconds, until your leg is almost straight.
Read the video text
Seated or lying? +14% hamstring growth with seated curls, versus 9% lying (Maeo et al., 2021). More activity in the lower hamstring with the curl than the deadlift (Schoenfeld et al., 2015). 51% fewer hamstring injuries with the Nordic curl (van Dyk et al., 2019). Hip and knee: both movements. The video ends by showing how to create the routine in Progrevia.
Seated or lying leg curl
| Muscle | Seated curl | Lying curl |
|---|---|---|
| Hamstrings overall | +14% | +9% |
| Those crossing hip and knee | +8% to +24% | +4% to +19% |
| Short head of biceps femoris (knee only) | +10% | +9% |
The advantage of the seated curl appears precisely in the muscles that cross the hip, the ones stretched when you sit. In the short head, which only crosses the knee, both gave the same. If your gym has both machines, prioritise the seated one; if it only has the lying one, it is still a good exercise.
Leg curl or Romanian deadlift: they do not compete
In 2015, Brad Schoenfeld (CUNY Lehman College, New York) compared the lying leg curl with the stiff-leg deadlift in 10 trained men, both with their 8-rep load and to failure. The curl activated the lower part of the hamstrings, the part nearest the knee, more. Each exercise loads a different area of the muscle, so the sensible thing is to do both. We cover it in leg exercises.
The Nordic curl and hamstring injuries
The Nordic curl is a bodyweight leg curl: kneeling, ankles held down, you lower yourself forward braking with your hamstrings. In 2019, Nicol van Dyk (Aspetar hospital, Doha) pooled 15 studies with 8,459 athletes. Prevention programmes that included the Nordic curl cut hamstring injuries by up to 51%: practically in half.
If you run, play football or sprint, it is one of the best-supported exercises for protecting those muscles. We look at it in strength training for runners.
Common leg curl mistakes
- Lifting your hips: lying down, if your hips rise, the weight is too heavy.
- Knee out of line with the machine: the movement feels awkward and loads the joint badly.
- Half reps: bend the knee fully and straighten it almost fully.
- Dropping the weight on the way down: the descent is the part that works the stretched muscle most.
- Starting the Nordic with no progression: it causes strong soreness; start with few reps and lower only part of the way.
How to program the leg curl
- Sets and reps: 2-4 sets of 8-15 reps, 1-3 reps short of failure.
- Frequency: 1-2 times a week, on your leg days.
- What to pair it with: a hip exercise, such as the Romanian deadlift or the hip thrust, in the same week.
- Nordic curl: 2-3 sets of 4-8 reps, gradually increasing the range. We explain it in progressive overload.
Safety: if you feel a sharp pain at the back of the thigh, stop the set. With discomfort that does not go away, see a healthcare professional before loading again.
The Progrevia generator can include the leg curl on your leg days, seated, lying, on a cable or with a band depending on your equipment, and leaves it out if you mark a hamstring injury.
- Maeo S, Huang M, Wu Y, Sakurai H, Kusagawa Y, Sugiyama T, et al. Greater Hamstrings Muscle Hypertrophy but Similar Damage Protection after Training at Long versus Short Muscle Lengths. Medicine and Science in Sports and Exercise. 2021;53(4):825-837.
- Schoenfeld BJ, Contreras B, Tiryaki-Sonmez G, Wilson JM, Kolber MJ, Peterson MD. Regional differences in muscle activation during hamstrings exercise. Journal of Strength and Conditioning Research. 2015;29(1):159-164.
- van Dyk N, Behan FP, Whiteley R. Including the Nordic hamstring exercise in injury prevention programmes halves the rate of hamstring injuries: a systematic review and meta-analysis of 8459 athletes. British Journal of Sports Medicine. 2019;53(21):1362-1370.
Progrevia · · How we write our guides
Frequently asked questions
Which muscles does the leg curl work?
The hamstrings: semitendinosus, semimembranosus and biceps femoris, in their knee-bending role. The calves also help a little.
Is the seated or lying leg curl better?
Seated. In Maeo's study (2021), the hamstrings grew 14% with the seated curl versus 9% with the lying one, because seated they work in a more stretched position.
Do I need leg curls if I already do Romanian deadlifts?
Yes. The deadlift works the hamstrings from the hip and the curl from the knee, and each activates a different area of the muscle more (Schoenfeld, 2015).
Does the Nordic curl prevent injuries?
Yes: in van Dyk's meta-analysis (2019) of 8,459 athletes, programmes that included it cut hamstring injuries by up to 51%.
How many sets of leg curls should I do?
2-4 sets of 8-15 reps, 1-3 reps short of failure, 1-2 times a week, alongside a hip exercise such as the Romanian deadlift.
Informational content based on the available scientific evidence: it does not replace advice from a healthcare professional. If you have an injury or a medical condition, or are pregnant, check with one before changing your training or diet.
