Lying leg curls on a leg extension curl machine train the hamstrings face down, with the ankles hooked under a roller and the knees lined up to the machine pivot. The movement also gets filed under a second name, prone leg curl, and that naming split is where most of the confusion starts.
This guide covers the details that decide whether you feel it in your hamstrings or your low back: pad height, ankle position, hip control, tempo, load, and weekly frequency. You will also see when a seated or single-leg curl fits better.
Quick Answer: Lying leg curls on a leg extension curl machine are performed face down with the ankles under the curl roller and the knees aligned to the pivot, and the same exercise is also called a prone leg curl. Set the pad just above the heels, keep the hips down, lower for about three seconds, and use a load you can curl for 8 to 12 clean reps.
Key Takeaways
- Two names, one movement: Lying leg curl and prone leg curl describe the same face-down knee flexion, and prone is simply the anatomy term for chest down.
- Pads set the joint: The ankle roller sits just above the heels and the thigh pad traps the hips so the knee stays aligned with the machine pivot.
- Ankle choice is a feel decision: Toe position changes calf involvement and measured force, not hamstring activation, so pick the position you can hold without cramping.
- Hips down is the whole game: A pelvis that lifts turns a hamstring curl into a low back extension, and the fix is less load plus a harder brace.
- Two sessions is enough: Two sets of 8 to 12 reps twice a week, lowered under control, covers most home gym lifters.
What Does Lying Leg Curl Mean on a Leg Extension Curl Machine?
The label lying leg curl describes the same face-down knee flexion you will also see written as a prone leg curl, because prone means chest down in anatomy. On a combo machine, the curl station is the side where your shins press against a roller instead of your feet driving a shin pad, and you use it while lying on your stomach. A 2022 review of hamstring force-length data reports that knee flexion exercises performed with hip angles of 45 to 90 degrees promote more optimal force generation [1].
Why the same movement is filed under two names
Gym chains, search results and coaching cues borrow from different vocabularies, so the identical drill shows up as lying curl, prone curl or reverse curl within the same week. The anatomy term is prone, the everyday term is lying, and neither label changes the setup, the pad order or the muscles that do the work.
What the two pads on the machine are actually for
The upper pad traps your thighs so your pelvis cannot rotate, and the lower roller is the only part that should travel during a rep. Treat the thigh pad as the anchor and the ankle roller as the handle, and the curl stops behaving like a whole-body lift.
- Prone: The clinical word for face down, which is why textbooks and product pages use it interchangeably with lying.
- Lying curl station: The side of a combo machine built for knee flexion, usually marked by a roller that sits behind the ankles.
- Extension station: The other side of the same frame, where the roller sits on the front of the shins and the knee extends instead of flexing.
Combo frames put both movements on one footprint, so confirm which station you are on before loading the stack, and read leg extension vs leg curl if the two still blur together. For a broader tour of the category, this explainer on what a leg curl machine does covers the seated, lying and standing versions.
"The leg extension/curl machine is such a great machine especially at that price point. It is another great RitFit machine for my gym!"
Westley W. Verified Buyer, RitFit PLC01 Leg Extension Curl Machine
Set the Pads Before You Lie Down
Pad setup decides whether the curl loads your hamstrings or your joints, and the two settings that matter are ankle roller height and knee alignment with the pivot. On the RitFit PLC01 leg extension curl machine, the curl station pairs a thigh pad with an ankle roller, so your adjustment is really the gap between those two pads.
Ankle pad height and knee axis
Set the roller just above the heels so it pulls the shin down instead of crushing the foot, then check that your knee joint sits level with the machine pivot. A knee that hangs below or above the pivot changes the resistance curve and often shows up as a pinch at the front of the knee.
- Too high: The roller rides the calf, the shin gets pushed forward, and the top of the rep feels like a calf cramp.
- Too low: The roller catches the heel, the foot slides, and you lose the last few degrees of knee flexion.
- Just right: The pad crosses the lower calf, the heel clears it, and your ankle can still move a little.
Getting the legs under the roller without twisting
Lie face down first and pull your hips toward the thigh pad, then slide one leg under the roller at a time so your pelvis never rotates to make room. Settle your forehead on the bench or turn your head to one side, grip the handles, and let the thigh pad take your weight before you move the stack.
Long femurs and short shins both create fit problems, so adjust the thigh pad before you assume the machine is wrong for you. The video below walks through the same station on the PLC01, including how the roller and thigh pad travel.
Point or Flex Your Toes: What Ankle Position Actually Changes
Ankle position changes how much your calf contributes and how much force you can produce, but it does not appear to change hamstring activation. The gastrocnemius crosses both the knee and the ankle, so plantarflexion shortens it while dorsiflexion lengthens it, and the hamstrings keep doing the same knee flexion job either way.
- Toes pointed: The calf is short and quiet, the set usually feels cleaner, and many lifters report less pulling behind the knee.
- Toes pulled up: The calf is long and active, the set feels harder near the top, and cramping becomes more likely in the first few sessions.
- Toes relaxed: A middle option that works well for high-rep sets when ankle tension starts stealing focus from the hamstrings.
Force output does move with ankle angle even when muscle activity does not.
- Measured difference: One study of 50 healthy young male rugby players measured peak eccentric force during the Nordic curl at 3.8 N/kg with the ankle plantarflexed and 3.5 N/kg with the ankle dorsiflexed [2].
Those numbers come from a bodyweight Nordic curl rather than a weight stack, so treat them as a direction rather than a target for your machine.
The practical takeaway is smaller than social media suggests: pick one ankle position, hold it for the whole set, and stop changing it mid-rep. If your calves cramp before your hamstrings fatigue, relax the toes and reduce the load rather than chasing a calf burn.
Why Do Your Hips Lift Off the Pad?
Your hips lift because the stack is heavier than your hamstrings can move at that joint angle. The pelvis rotates and the lumbar erectors take over to finish what the hamstrings cannot.
Common mistakes that lift the hips
Most hip lift traces back to one of four setup or loading errors, and each one has a simple correction you can make between sets.
- Load is too heavy: Drop one pin or one small plate and the hips usually stay down without any other change.
- Ribs are flared: Exhale, pull the lower ribs toward the pad, and brace as if someone were about to poke your stomach.
- Thigh pad is loose: Close the gap so the pad presses the back of the thighs and blocks hip rotation before it starts.
- Tempo is rushed: A fast lowering phase throws the pelvis up at the bottom, while a controlled one keeps the hips glued down.
Watch the back of your waistband rather than the mirror. If the gap between your lower back and the pad grows during the set, you have already lost the position and the remaining reps belong to your spine.
Bracing is a skill, so practice it with an empty stack first: three slow reps with the ribs down and the glutes relaxed. Once that feels automatic, add load until the pelvis starts to hint at lifting, then back off one step.
Lower the Weight Slower Than You Curl It
A controlled lowering phase is what turns the face-down curl into a training stimulus instead of a stack drop, and a three-second lower is a workable default. The hamstring is loaded while it lengthens on the way down, so rushing that half of the rep hands the work to momentum and gravity.
Count the lowering phase in your head rather than guessing at it. A simple four-count down and a one-count up keeps the set honest, and the extra time under tension exposes a stack that is too heavy within the first two reps.
- Own the bottom: Pause for a half second with the knees nearly straight before you curl again.
- Finish the top: Bring the roller as close to your glutes as your knees allow without lifting the hips.
- Skip the bounce: Letting the stack tap down between reps removes the hardest part of the range.
Range of motion is part of the same standard, because a short rep that stops halfway is a lighter rep wearing a heavier load. Dr. Mike Israetel, PhD, co-founder of Renaissance Periodization, draws the line clearly in his hamstring guide.
"Always start from a fully extended knee and always bring the pad to touch your butt with each rep. If you can't touch the pad to your butt, it doesn't count as a rep unless you're purposefully training lengthened partials."
Dr. Mike Israetel, PhD, PhD in Sport Physiology, Renaissance Periodization, Complete Hamstring Training Guide
Pick a Load You Can Curl Without Bridging
Pick a load light enough that you can lower for three seconds and curl for 8 to 12 reps with your pelvis flat on the pad. That load is almost always lighter than the one you can swing, and the difference between the two is the difference between a hamstring set and a low back set.
Judge the load by the last rep, not the first one. If rep twelve looks like rep one, the stack is too light, and if rep six turns into a hip bridge, the stack is too heavy.
Rep ranges and when to add weight
Stay in the 8 to 12 rep range for two or three sets, and add the smallest available increment once you can complete the top of the range on every set with the same tempo. A pin, a half plate or a magnetic add-on is enough, and there is no reason to jump two increments at once.
- Add load when: Both sets hit 12 clean reps, the lowering phase still takes three seconds, and the hips never leave the pad.
- Hold load when: Reps are clean but the last one slows down, which is a normal place to sit for a week or two.
- Drop load when: The roller path shortens, the pelvis lifts, or you need a bounce to finish the top.
Rough strength targets help you sanity check the stack rather than chase a number. Most lifters curl noticeably less than they can extend, so a face-down curl that matches your leg extension load is a sign the hips are helping.
Program the Face-Down Curl Twice a Week
Two sessions per week gives the hamstrings enough practice to grow without burying your leg days, and it fits neatly after a squat or hinge pattern. Place the curl after the big movement so the hamstrings are warm but not pre-fatigued, and keep the sets short enough that the last rep still looks like the first.
- Beginner: Two sets of 8 to 10 reps twice a week, with one or two reps left in the tank on each set.
- Intermediate: Three sets of 10 to 12 reps twice a week, adding load when all sets reach the top of the range.
- Advanced: Three sets plus one back-off set at a lighter load, still inside the same two sessions.
Progress by owning the rep before you own the plate. A clean extra rep at the same tempo is a real gain, while a heavier stack with a shorter range is usually a step sideways.
Pair the curl with a hip hinge on the same day so the hamstrings get both a knee flexion and a hip extension stimulus. If your program already includes Romanian deadlifts, keep the curl volume modest and let the hinge carry the heavier loading.
Lying Leg Curl vs Seated Leg Curl vs Standing Single-Leg Curls
All three versions flex the knee, and the meaningful difference is the hip angle, because the hamstrings cross both joints. A face-down curl keeps the hip near neutral, which shortens the biarticular hamstrings, while a seated curl moves into hip flexion and trains them at a longer length.
Growth data favors the seated position, which surprises most lifters who assume the face-down version is the default.
In a 12-week within-person trial, seated leg curl training increased whole hamstring muscle volume by 14% versus 9% for prone training, and the protocol used 70% of 1RM for 10 reps and 5 sets, twice per week [3].
The same trial found that both positions reduced susceptibility to muscle damage in a follow-up eccentric-only session.
- Face-down curl: Best for strict isolation and an easy hip position, and the version most combo machines do well.
- Seated curl: Trains the hamstrings at a longer length, which the trial linked to more volume gain in the biceps femoris and semimembranosus, and it is easier to load heavy.
- Standing single-leg curl: Adds a balance and anti-rotation demand, and it exposes side-to-side differences the two-legged versions hide.
None of that makes the face-down curl a bad choice. It is the version most people can set up in a garage, it pairs well with a hinge, and the trial still showed a real 9% volume gain across twelve weeks.
If the naming still feels slippery, the prone (face-down) leg curl setup covers the same movement from the other label, and the prone vs seated leg curl comparison goes deeper on which position deserves the heavier loading.
Swap the Movement When the Setup Does Not Fit
Swap the movement when your hips cannot stay on the pad or the roller will not line up with your knee. Pad geometry, shin length and femur length all decide whether a curl station fits, and a curl you cannot set up correctly is not a character test.
- Seated curl: The closest substitute and the one with the strongest growth data, if your machine has that station or you have gym access.
- Single-leg curl: Same station, one leg at a time, which often fixes a hip that will not stay down on two legs.
- Nordic or slider curl: Bodyweight options when the machine pad is too short, though the loading is harder to fine tune.
- Smith machine curl: A bar-based setup for lifters without a curl station, covered in this guide to lying leg curls on a Smith machine.
When to stop the set
Stop the set when the pelvis lifts, when the roller path shortens, or when you feel a sharp pull behind the knee rather than a working burn in the belly of the hamstring. A cramp that does not release within a few seconds, swelling, or pain that lingers after the session is a reason to stop training the movement and get it looked at.
Mild soreness in the muscle belly a day later is normal for a new movement. Sharp, localized or joint-line pain is not, and no program is worth training through it.
If you are still shopping for the frame itself, these beginner-friendly leg extension curl machine picks explain what to look for, and the leg machines for a home gym collection shows the current range. More options for training the same muscles without a machine live in this list of leg curl alternatives for home training.
FAQs About Lying Leg Curls
Is a lying leg curl the same as a prone leg curl?
Yes. Lying leg curl and prone leg curl name the same face-down knee flexion movement, and prone simply means face down in anatomy language. Either search term should lead you to the same pad setup and the same hamstring action, so you can follow instructions written under either name without changing anything about how you train.
Where should the ankle pad sit on my lower leg?
Set the ankle pad just above the heels, across the lower calf and Achilles area, so the pad pulls the shin down rather than digging into the foot. The pad should sit low enough that your toes clear it and high enough that your ankle joint stays free, and the knee should line up with the machine pivot before you add any weight.
Should I point or flex my toes during a lying leg curl?
Either position works, and the choice changes calf involvement more than hamstring involvement. Flexing the toes toward your shin lengthens the gastrocnemius and can make the set feel harder behind the knee, while pointing the toes shortens it and often feels more comfortable, so pick the position you can hold for every rep without cramping.
How much weight should a beginner use on a lying leg curl?
Start with a load you can lower for three full seconds and curl for eight to twelve clean reps without your hips lifting. That is often lighter than the stack you can swing, so expect to begin with a small plate or the first few pins, and add weight only after you own the top of the range on both sets.
Why do my hips lift off the pad during face-down curls?
Your hips lift because the weight is heavier than your hamstrings can move at that knee angle, so your body recruits the low back and glutes to finish the rep. Reducing the load, bracing your ribs down, and stopping the set when the pelvis starts to rise will keep the work on the hamstrings and off your lumbar spine.
How many times a week should I do lying leg curls?
Two sessions per week is enough for most home gym lifters, placed after your squat or hinge work so the hamstrings are not pre-fatigued. Keep two or three sets per session, leave one or two reps in reserve, and add a small amount of load or one rep each week instead of adding extra sessions.
Can I use a leg extension curl machine if the pad does not fit my legs?
Sometimes the thigh pad is too short for long femurs or the ankle roller sits too high for shorter shins, and forcing the fit turns the curl into a low back exercise. If you cannot line the knee up with the pivot, switch to a seated curl, a single-leg curl, or a Nordic style variation rather than fighting the machine.
Conclusion
Lying leg curls on a leg extension curl machine are a face-down knee flexion you may also know as a prone leg curl. The setup does most of the work: roller above the heels, knees on the pivot, hips pinned, three seconds down.
Train them twice a week with a load you can control, and treat a lifting pelvis as the signal to stop the set. Film one set from the side and compare your hips and roller path against the cues above, then check the current RitFit discount codes before you add a second station.
Disclaimer
This article provides general fitness education and does not replace evaluation by a qualified medical or physical therapy professional. Consult a licensed clinician before starting a new hamstring program if you have knee, hip, or low back pain, a recent injury, or a history of hamstring strain.
References
1. Kellis E, Blazevich AJ. Hamstrings force-length relationships and their implications for angle-specific joint torques: a narrative review. BMC Sports Sci Med Rehabil. 2022;14(1):166. doi:10.1186/s13102-022-00555-6. PMCID: PMC9446565
2. Nishida S, Ito W, Ohishi T, Yoshida R, Sato S, Nakamura M. The Effect of Ankle Position on Peak Eccentric Force during The Nordic Hamstring Exercise. J Sports Sci Med. 2022;21(1):43-48. doi:10.52082/jssm.2022.43. PMCID: PMC8851116
3. Maeo S, Huang M, Wu Y, et al. Greater Hamstrings Muscle Hypertrophy but Similar Damage Protection after Training at Long versus Short Muscle Lengths. Med Sci Sports Exerc. 2021;53(4):825-837. doi:10.1249/MSS.0000000000002523. PMCID: PMC7969179
