Romanian deadlifts and lying leg curls belong to different movement slots. The Romanian deadlift fills the hinge slot, while the leg curl fills the knee-curl slot. Use both when the programme deliberately includes both, not because every leg day needs a fixed pair.
For complete leg-day planning, use Forte's best leg day exercises guide. This page answers a smaller question: what job is the exercise doing in the session?
The hinge job
A hinge asks you to control the load while the hips travel back and forwards. Forte's current Romanian Deadlift page is the exact hinge entity for this comparison.
Exercise
Romanian Deadlift
Muscles worked
Setup: Put a barbell in front of you on the ground and grab it using a pronated (palms facing down) grip that a little wider than shoulder width. Tip: Depending on the weight used, you may need wrist wraps to perform the exercise and also a raised platform in order to allow for better range of motion.
Bend the knees slightly and keep the shins vertical, hips back and back straight. This will be your starting position. Keeping your back and arms completely straight at all times, use your hips to lift the bar as you exhale. Tip: The movement should not be fast but steady and under control. Once you are standing completely straight up, lower the bar by pushing the hips back, only slightly bending the knees, unlike when squatting. Tip: Take a deep breath at the start of the movement and keep your chest up. Hold your breath as you lower and exhale as you complete the movement. Repeat for the recommended amount of repetitions.
Coach's tip
- Keeping your back and arms completely straight at all times, use your hips to lift the bar as you exhale. Tip: The movement should not be fast but steady and under control.
- Once you are standing completely straight up, lower the bar by pushing the hips back, only slightly bending the knees, unlike when squatting. Tip: Take a deep breath at the start of the movement and keep your chest up. Hold your breath as you lower and exhale as you complete the movement.
- Repeat for the recommended amount of repetitions.
The entity page supplies the exercise identity and setup. It does not supply your load or give permission to train through pain.
The curl job
A lying leg curl gives the session a knee-curl exercise. The exact public route below is verified. Use the setup written on the exercise page and in your programme rather than treating every curl machine as identical.
Exercise
Lying Leg Curls
Muscles worked
Setup: Adjust the machine lever to fit your height and lie face down on the leg curl machine with the pad of the lever on the back of your legs (just a few inches under the calves). Tip: Preferably use a leg curl machine that is angled as opposed to flat since an angled position is more favorable for hamstrings recruitment.
Keeping the torso flat on the bench, ensure your legs are fully stretched and grab the side handles of the machine. Position your toes straight (or you can also use any of the other two stances described on the foot positioning section). This will be your starting position. As you exhale, curl your legs up as far as possible without lifting the upper legs from the pad. Once you hit the fully contracted position, hold it for a second. As you inhale, bring the legs back to the initial position. Repeat for the recommended amount of repetitions.
Coach's tip
- As you exhale, curl your legs up as far as possible without lifting the upper legs from the pad. Once you hit the fully contracted position, hold it for a second.
- As you inhale, bring the legs back to the initial position. Repeat for the recommended amount of repetitions.
Two slots, one deliberate choice
The labels describe the role in this article. They do not claim that either exercise works only one joint or muscle.
| Slot | What the session is asking for | What does not substitute |
|---|---|---|
| Hinge slot | Move a load through a hip-hinge pattern, using the exact exercise the programme names. | A knee-curl exercise. It does not fill the hinge slot. |
| Knee-curl slot | A knee-curl exercise, kept at the catalogue name and setup. | A hinge, or a different curl swapped in for variety. |
The rule this leaves you with
- Read the written session and mark which slot each exercise fills. Most sessions name one, not both.
- Add the second slot only when something gives it a reason. The programme, or a qualified coach. Not a habit of pairing them.
Source note: slot labels come from how each movement is classified, not from a comparison of outcomes. No study on this page says one is better than the other.
When both can make sense
Both make sense when the programme wants a hinge and a knee-curl slot in the same session or across the week. PPL currently places Romanian Deadlift and Leg Curls in Legs A. That is a real example of the pairing, not proof that every reader should copy the session.
Programme
PPL (Push Pull Legs)
The classic 6-day Push Pull Legs split. Train each muscle group twice per week with optimal volume distribution. Push day for chest, shoulders, and triceps. Pull day for back and biceps. Leg day for lower body. The gold standard for building muscle.
- Train each muscle 2x/week
- Optimal volume distribution
- Progressive overload focus
- Balanced development
If your current plan already includes both, follow its order and progression. If it includes one, do not add the other simply because this article explains the difference. Check the week's total work and ask a qualified coach when the reason is unclear.
When one may be enough for the session
One may be enough when the written session has a narrower purpose, when the other job appears elsewhere in the week, or when adding more would exceed the plan. Read the whole week before adding work to make one day look complete.
Read the exact exercise, not the family name
"Deadlift" describes a family of exercises. This comparison is about the exact Romanian Deadlift page above. Do not swap in a conventional, stiff-leg, trap-bar, or dumbbell variation and assume the same setup applies.
The same caution applies to curls. Lying and seated curls are different catalogue identities. Follow the exact version written in the session.
Check where the jobs appear across the week
Before adding an exercise, read every lower-body session in the week. A hinge may already appear on another day. A curl may be placed after a demanding lift or in a separate session. The weekly arrangement matters more than making one day look complete on paper.
If you still cannot explain the arrangement, keep the programme unchanged and ask. A useful question for a coach is specific: "This week has Romanian Deadlift here and Lying Leg Curls there. What job does each one have, and what would be lost if I removed one?"
Technique and pain boundaries
Stop a set if you cannot control the movement or if it causes pain. Do not use this page to diagnose a hamstring, hip, knee, or back problem. A coach can review technique; a healthcare professional can assess pain or injury.
Frequently asked questions
Is a deadlift better than a leg curl?
No universal winner is claimed here. They have different jobs in the article, and the current programme decides which belongs in the session.
Can one exercise replace the other?
Not as a like-for-like swap. One is the hinge in this comparison and one is the knee-curl exercise. Change the written session only when the programme or a qualified coach gives you a reason.
References
- Romanian Deadlift, Lying Leg Curls, and the PPL programme page, accessed 26 August 2026.
- Muscle Activation Patterns of the Proximal Medial and Distal Biceps Femoris and Gluteus Maximus Among 6 Hip Extension and Knee Flexion Exercises in Trained Women. PMID 35989703.