Biomechanics & Exercise Science5 min readIntermediate
Seated vs lying leg curl: which is better for your hamstrings?
Both machines bend the knee against resistance, so they look almost the same. The difference is your hip. Sitting bends the hip, which stretches the hamstrings, so they work from a longer position than when you lie flat.
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The short answer
The seated leg curl is usually the better choice for hamstring size. In a 12-week study, the leg trained with seated curls grew about 14% in hamstring volume against about 9% for lying curls in the other leg (Maeo et al., 2021). The lying curl still builds muscle, so use it if it suits you better.
- Both exercises build muscle. Seated is the better default, not the only option.
What is the difference between seated and lying leg curls?
Three of the four hamstring muscles cross both the hip and the knee. Bending the hip lengthens them, and a muscle that works from a longer position tends to grow more (Warneke et al., 2023).
Which leg curl builds more muscle?
The short head of the biceps femoris, which crosses only the knee, grew similarly with both. The extra growth came from the muscles that cross the hip.
How to use seated and lying leg curls
- Make the seated curl your main hamstring curl.
- Lean forward slightly in the seat to stretch the hamstrings a little more.
- Use lying curls if the seated machine is busy or does not fit you.
- Pair either curl with a hip hinge such as the Romanian deadlift.
See the best stretched-position exercise for every muscle with the muscle-length exercise finder.
Common leg curl mistakes
- Lifting the hips off the pad to move more weight.
- Cutting the stretch short at the start of each rep.
- Letting the weight drop instead of lowering it under control.
People also ask
How many sets of leg curls should I do?
Most people do well with 2–4 hard sets, once or twice a week, alongside a hip hinge.
Is the seated leg curl better than the lying leg curl?
For hamstring size, usually yes. In a direct comparison, seated curls built more muscle.
Should I do both leg curls?
You can. Seated is the better default, but lying curls still build muscle and add variety.
Why does sitting make a difference?
Sitting bends the hip, which stretches the hamstrings while they work.
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Scientific References & Evidence
- Maeo S. et al. (2021). Greater hamstrings muscle hypertrophy but similar damage protection after training at long versus short muscle lengths. Medicine & Science in Sports & Exercise, 53(4), 825–837. Available at: https://doi.org/10.1249/MSS.0000000000002523 (Accessed: 23 August 2026).
- Warneke K. et al. (2023). Physiology of stretch-mediated hypertrophy and strength increases: a narrative review. Sports Medicine, 53(11), 2055–2075. Available at: https://doi.org/10.1007/s40279-023-01898-x (Accessed: 23 August 2026).
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Educational information for adults aged 18 and over. It does not diagnose, treat or manage any medical condition. If you have a health condition, or symptoms that worry you, speak to your doctor or a health professional.