09/02/2026
**SEATED LEG CURL vs. LYING LEG CURL vs. RDL — WHICH BUILDS MORE HAMSTRING? 🦵**
Ill give you the answer 1st and then you can read why below:
**So what's the winner?**
For overall development, don't choose just one.
**Seated curls = phenomenal lengthened knee-flexion stimulus.**
**RDLs = heavy lengthened hip-extension stimulus.**
**Lying curls = useful additional knee-flexion volume.**
If I were prioritizing pure hamstring mass:
Seated Leg Curl
Romanian Deadlift
Lying Leg Curl
The best hamstrings aren't built by finding one magical exercise.
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If your goal is **maximum hamstring growth**, exercise selection matters.
**SEATED LEG CURL**
In a 12-week study, seated leg curls increased total hamstring muscle volume by approximately **14%**, compared with about **9%** from lying/prone leg curls.
Why the difference? Sitting puts your hips into flexion, which stretches the hamstrings at the hip while you train knee flexion. That means you’re loading the hamstrings in a **longer muscle position** — and research continues to show that lengthened-position training can be extremely effective for hypertrophy.
**LYING LEG CURL**
Still a great hamstring exercise — and **9% growth is nothing to complain about**. But with the hips relatively straight, the hamstrings start in a shorter position than they do during the seated version.
**ROMANIAN DEADLIFT**
RDL research has also shown roughly **10% increases in hamstring cross-sectional area** in relatively short training periods, with other research showing specific hamstring muscles such as the semimembranosus increasing around **11%** with stiff-leg deadlift training.
But RDLs aren't simply another leg curl.
They train the hamstrings primarily through **HIP EXTENSION**, while curls train them through **KNEE FLEXION**.
