Lying Leg Curl vs Seated Leg Curl
Both machines bend the knee against a load and work the hamstrings. The difference is the hip: lying, it's straight; seated, it's bent and the muscle is more stretched.
| Lying Leg Curl | Seated Leg Curl | |
|---|---|---|
| Muscles | hamstrings, calves | hamstrings under stretch |
| Equipment | Machine | Machine |
| Entry bar | 1/3 fine from your first workout | 1/3 fine from your first workout |
| Pick it when | It's the one you have, or you want to feel the muscle better. | You want more hamstring stretch and your gym has the machine. |
The main difference
The hamstrings cross both the knee and the hip. Seated, your hip is flexed, so the muscle starts the movement stretched — and in a study by Maeo et al. (2021) the hamstrings grew noticeably more after seated curls than after lying ones. Lying, the hip is straight and the muscle shorter, but it's easier to feel it working and the calves join in more. In practice both are good; use whichever machine your gym has and use the full range.
Can you do both
Yes: one on leg day, the other on your second day, or both for 2–3 sets. Curls pair well with Romanian deadlifts, which load the same muscle through the hip.
In which programs
Log both in the diary — your estimated max will show which one is growing faster for you.