HamstringsMachineBeginner

How to Do a Lying Single Leg Curl

By Bryan Alger, Co-Founder of Gravitus

· Updated Nov 11, 2026

A lying single leg curl is a lying leg curl done one leg at a time. Lie face down with your kneecaps just off the pad, hook one ankle under the roller and curl your heel toward your glute. It trains the hamstrings of each leg on their own, with the calf helping. Most lifters do 3 sets of 8 to 15 reps per leg.

Sets x reps 3 x 8-15 per leg

Median 10-rep weight, per leg 5022.5 lbkg men 3014 lbkg women

Muscles Hamstrings, calves

Setup Kneecaps off the pad, weaker leg first

Technique

How to do a lying single leg curl

Set the ankle pad so it will sit on your lower calf, just above your heel, with your leg straight.
Lie face down with your kneecaps just off the end of the thigh pad and your knees in line with the machine's pivot. Hold the handles.
Hook your weaker leg under the pad. Let the other leg rest straight on the bench, clear of the roller.
Press both hips into the bench and curl your heel toward your glute as far as the pad allows. Pause for a second.
Lower over 2 to 3 seconds until your knee is almost straight, without letting the plates touch. Finish the set, then do the same weight with the other leg.

Setup

Setting up for one leg

Weaker legGoes firstStart every round with it while you are fresh. Its reps set the target for the other side.

Resting legOff the rollerLeave it straight on the bench beside the pad. If it touches the roller, it is helping.

HipsSquare and downOne working leg pulls your pelvis toward that side. Grip the handles and keep both hips on the bench.

Same pinBoth sidesUse the same weight on each leg, so your log shows the gap and whether it is closing.

The machine setup is the same as for two legs: kneecaps off the pad, knee on the pivot, ankle pad just above the heel. Much of what we know about the lying curl comes from one-leg training. In the 12-week study that compared lying and seated curls, each person trained one leg lying and the other leg seated (Maeo 2021). The study on toe position also trained one leg each way (Cadeo 2023).

Gravitus data

How much weight should you use for a lying single leg curl?

On Gravitus, the median man lifts 50 lb (22.5 kg) per leg for 10 reps on the lying single leg curl, and the median woman 30 lb (14 kg).

Men, typical 50 lb per leg for 10 reps

Most lift: 40 to 70 lb
Top 10% lift: 90 lb or more
Starting out: under 40 lb

Women, typical 30 lb per leg for 10 reps

Most lift: 22.5 to 37.5 lb
Top 10% lift: 50 lb or more
Starting out: under 22.5 lb

Men, typical 22.5 kg per leg for 10 reps

Most lift: 18 to 30 kg
Top 10% lift: 40 kg or more
Starting out: under 18 kg

Women, typical 14 kg per leg for 10 reps

Most lift: 10 to 17 kg
Top 10% lift: 22.5 kg or more
Starting out: under 10 kg

One-rep max / 10-rep weight, per leg, rounded to 5 lb (2.5 under 40). From 1,415 men and 256 women who log the lying single leg curl on Gravitus, computed Nov 5, 2026 (Brzycki). Methodology
Percentile	Men	Women
25th	55 / 40 lb	30 / 22.5 lb
Median	70 / 50 lb	40 / 30 lb
75th	90 / 70 lb	50 / 37.5 lb
90th	120 / 90 lb	65 / 50 lb

One-rep max / 10-rep weight, per leg, rounded to 2.5 kg (1 under 20). From 1,415 men and 256 women who log the lying single leg curl on Gravitus, computed Nov 5, 2026 (Brzycki). Methodology
Percentile	Men	Women
25th	25 / 18 kg	13 / 10 kg
Median	30 / 22.5 kg	18 / 14 kg
75th	40 / 30 kg	22.5 / 17 kg
90th	52.5 / 40 kg	30 / 22.5 kg

These are one-leg weights. Leg curl machines use different cams and levers, so the same pin feels different from brand to brand. Do not compare them with your two-leg number either. Compare yourself to your own log on the same machine, one side against the other.

One leg vs two

How much should one leg lift compared with two?

Not simply half. In the lab, untrained people were weaker with both legs together than with their two legs added up, while trained weightlifters were stronger together (Howard 1991). Practice decides most of it: one-leg training raises one-leg strength more, and two-leg training raises two-leg strength more (Kassiano 2025).

If you have only ever curled with two legs, start near 40% of your two-leg weight on each leg and let the reps tell you where to go. Use the same pin for both sides, and the weaker leg's reps become your target.

Anatomy

Muscles worked

HamstringsBend the knee. With the hip straight, the semitendinosus did the most work in a one-leg curl study (Mitsuya 2026) and grew the most, 19% in 12 weeks (Maeo 2021).

Primary

GastrocnemiusThe big calf muscle crosses the back of the knee and helps bend it. With your toes pulled up it helps more, so you lift more weight (Cadeo 2023).

Secondary

Compare

Lying single leg curl vs lying leg curl vs seated single leg curl

Attribute	Lying single leg curl	Lying leg curl	Seated single leg curl
Weight you log	One leg	Both legs	One leg
Hip position	Bent slightly	Bent slightly	Bent about 90 degrees
Shows a side gap	Yes	No	Yes
Time per set	Twice as long	Shortest	Twice as long
Best for	Evening out sides	Hamstring volume fast	Most hamstring growth

Verdict

For size, sitting matters more than one leg or two. Trained one leg at a time for 12 weeks, the seated curl grew the hamstrings 14% and the lying curl 9% (Maeo 2021). Across nine studies, one-limb and two-limb training grew muscle the same (Kassiano 2025). Use the lying single leg curl to even out your sides, or when there is no seated machine.

Programming

Sets, reps and progression

3Sets per leg

8-15Reps

0-2Reps left

Stop each set 0 to 2 reps short of failure. Sets taken close to failure build muscle across a wide range of reps (Schoenfeld 2021). In the 12-week study, the one-leg lying curl was 5 sets of 10 at 70% of max, twice a week (Maeo 2021).

Stack plates are a big jump for one leg. Add reps first: when both legs reach 15, move the pin down one plate and go back to 8 to 10.

Form

Common mistakes

Stronger leg firstIt sets a target the weaker leg cannot match. Start every round with the weaker leg.
Hips twisting or liftingOne working leg pulls your pelvis up and to the side. Grip the handles, press both hips down and go lighter.
Resting leg helpingKeep it straight on the bench and clear of the roller.
Kneecap on the padYour knee sits off the pivot and the roller slides along your calf. Slide down until your kneecaps clear the pad.
Stopping short of straightThe leg is most stretched when the knee is almost straight. Lower all the way on every rep.
Dropping the weightLower over 2 to 3 seconds and keep the plates off the stack between reps.

Variations

Single leg curl variations

Seated single leg curlOne leg at a time with your hips bent. The seated leg grew 14% against 9% for the lying leg in 12 weeks (Maeo 2021).

Standing single leg curlOne leg at a time standing, with the hip straight like the lying curl.

Lying leg curl, both legsBoth legs on the same machine. Quicker, with a heavier number.

Seated Leg CurlBoth legs with the hips bent. The curl that grew the hamstrings most.

Nordic Hamstring CurlKneel with your ankles held and lower your body forward under control. Bodyweight and very hard.

Romanian DeadliftTrains the hamstrings at the hip instead of the knee. Pair it with a curl.

FAQ

Questions people ask

What are the benefits of single leg curls?

Each hamstring does its own work, so a weaker side cannot lean on the stronger one, and your log shows the gap. One-leg training raises one-leg strength more than two-leg training (Kassiano 2025). It still builds muscle: done one leg at a time, the lying curl grew the hamstrings 9% in 12 weeks (Maeo 2021). And if one leg is hurt, training the other makes the resting leg stronger too, by 16.4% on average in leg studies (Manca 2017).

Are single leg curls better than double?

Not for muscle size. Nine studies found the same growth from one-limb and two-limb training (Kassiano 2025). Do them one leg at a time to see and close a gap between sides. Do both legs together to get more hamstring work done in less time.

What muscles do single leg curls work?

The hamstrings of the working leg, the semitendinosus most (Mitsuya 2026). The calf helps bend the knee. Your hip does not move, so the glutes do almost nothing.

Should I point or flex my toes on a single leg curl?

Either works. In a study that trained one leg each way for 10 weeks, toes up and toes pointed gave the same hamstring activity, strength and growth (Cadeo 2023). Toes up lets the calf help, so you lift more. Pick one and keep it the same on both legs.

Why is one hamstring weaker than the other?

A small gap between legs is normal, often from a dominant leg or an old injury. Two-leg curls can hide it, because the stronger leg can push more of the pad. Train the weaker leg first, use the same weight on both sides and log each one.

How much weight should I use for single leg curls?

For 10 reps, the median on Gravitus is 50 lb (22.5 kg) per leg for men and 30 lb (14 kg) for women. The strongest quarter lifts 70 lb (30 kg) and 37.5 lb (17 kg) or more.

Gravitus See where your lying single leg curl ranks

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References