Hamstring curl exercise: worth it, and which version

The leg curl has a reputation problem. Barbell people file it under "machine stuff for bodybuilders", somewhere between the pec deck and the vibrating plate. That's a mistake. The hamstring curl exercise trains the one job your deadlifts barely touch, and it does it with almost no fatigue for the rest of your body.

Short answer: yes, it's worth doing. Use the seated leg curl if your gym has one, the lying curl if it doesn't, and Nordics or slider curls if you have no machine at all. A lazy set at the end of leg day won't do much; two or three hard sets once or twice a week, next to a hinge, will round out your hamstrings properly. Below: what curls train, which version to pick, form, programming, and where they go in a running week, whether you plan it yourself or use an app that programs your lifts and your runs.

What the hamstring curl exercise trains (and what hinges miss)

Your hamstrings have two jobs. They extend the hip, which is what happens when you stand up out of a deadlift. And they bend the knee, which is what happens when you curl your heel toward your backside. Three of the four hamstring muscles cross both joints. The fourth, the short head of the biceps femoris, only crosses the knee.

Hinges load the hip side. Curls load the knee side. A plan that only does one is training half the muscle's job, which is why curls keep turning up in well-built runner-specific strength sessions next to an RDL or deadlift rather than instead of one.

The heavy lifts get you less hamstring work than gym lore suggests. If you've read how to do a deadlift, you know the conventional pull is mostly a leg-and-back lift. The hinges that do hammer the hamstrings are the Romanian deadlift and the glute-ham raise: in a 2014 EMG study of 12 weight-trained men comparing the leg curl, good morning, glute-ham raise and RDL at 85% of one-rep max, hamstring activity was maximized in the RDL and glute-ham raise. The leg curl wasn't the winner.

So the curl isn't the best hamstring exercise. It's the best way to cover the knee side cheaply. Those are different claims, and the second one is why it stays in the program.

Seated vs lying leg curl: which version to use

If your gym has both machines, this is the one question with a reasonably clear answer.

In a 12-week study, 20 adults trained one leg on a seated leg curl and the other on a lying (prone) leg curl, five sets of ten at 70% of one-rep max, twice a week. Whole-hamstring muscle volume increased more in the seated leg (+14%) than the prone leg (+9%). The authors concluded seated curls grew the hamstrings more effectively, and suggested training at long muscle lengths was the reason.

The logic is simple. Sitting flexes your hip, which stretches the two-joint hamstrings before the curl even starts. Lying flat leaves them shorter. More stretch under load, more growth, at least in this study. It's one trial in healthy adults, so treat it as a tiebreaker, not a law. But if you have the choice, pick the seated machine.

Every hamstring curl variation, by setup

Nordic hamstring curl

Kneel on a pad with your ankles held down by a partner, a loaded bar or a sturdy anchor. Keep your hips straight and lower your body toward the floor as slowly as you can, catch yourself with your hands, push back up. Most people can only control the lowering at first, and that's the point: it's a slow, heavy eccentric for the knee side of the hamstrings.

Slider or stability-ball curl

Lie on your back, heels on sliders or a ball, lift your hips into a bridge, then curl your heels toward you and push back out without letting your hips drop. You're extending the hip and bending the knee at once, so it's a better hamstring exercise than its equipment suggests. The single-leg version is a big jump in difficulty.

The Nordic and injury: what the research actually says

Nordics are usually sold as hamstring injury insurance. The evidence is more mixed than the sales pitch.

A 2019 meta-analysis of 15 studies concluded that injury prevention programs that include the Nordic reduced hamstring injuries by up to 51% across multiple sports. Then a 2021 reappraisal of the same evidence found only five of those 15 studies actually randomized people to the Nordic, and with more conservative methods called the protective effect inconclusive and mostly based on trials with a high risk of bias.

So: a reasonable exercise to include, studied mostly in team sports, and not a guarantee of anything. Do Nordics because they make your hamstrings strong at the knee. If you have a hamstring problem now, see a professional rather than a meta-analysis.

How to do a seated leg curl

1. ›Set the machine. Knee joint lined up with the machine's pivot. The lower pad sits just above your heels, the thigh pad snug on your thighs.
2. ›Sit tall. Back against the pad, hips all the way back. Hold the handles.
3. ›Start at full stretch. Legs nearly straight, hamstrings long. That stretched position is the part the seated-curl study above suggests matters most, so don't skip it.
4. ›Curl. Pull your heels down and back as far as the machine allows. Toes neutral or pulled toward your shins.
5. ›Lower slowly. Two to three seconds back to the stretched start. No bouncing out of the bottom.

For the lying curl the same rules apply: knees lined up with the pivot, hips pressed into the bench, full range, slow lowering.

Common hamstring curl mistakes

How to program hamstring curls

Coaching conventions, not commandments. RPE 8 means about two reps left in reserve.

Curls go after the main lifts, never instead of them. A typical lower-body day is a squat or deadlift, then a hinge or single-leg lift, then curls. Curls are an accessory, which is why they get higher reps and a lower priority than the barbell work.

Not every pull from the floor belongs in that slot. Power cleans for hybrid athletes train speed and power, not hamstring size, and they're a technical skill that needs coaching. They don't replace curls or hinges. Carries are the other easy add-on: a heavy farmer's walk after curls hits grip and trunk, and our guide to farmer's walk covers how heavy to go.

The best partner for a curl is still a hinge. If you train at home, the dumbbell RDL is the obvious pick, and romanian deadlift dumbbell form is the same hips-back hinge as the barbell version with a dumbbell in each hand. No dumbbells heavy enough? There are Romanian deadlift alternatives for every setup, from kettlebells to cables to single-leg work.

Progress the boring way: add reps until you hit the top of the range on every set, then add a little weight. For Nordics, progress the range and the speed of the lowering before you think about adding load.

Where hamstring curls fit a running week

Your hamstrings work hard in running, especially at speed. Sore hamstrings before a track session is a bad trade.

• ›Curl on an easy run day, or after the run on a hard day. Never heavy curls or Nordics the day before intervals, hill sprints or the long run.
• ›Introduce Nordics slowly. One or two sets for the first couple of weeks. They make hamstrings properly sore at first, and you don't want to find that out the day before a long run.
• ›Keep the load meaningful. A 2024 meta-analysis on middle- and long-distance runners found high-load strength training (at least 80% of one-rep max) improved running economy, while submaximal-load training did not show the same benefit. That's about your main lifts more than your curls, but it's a reason not to let a lower-body day become nothing but light machine work.
• ›Cut the volume in a race build. Two sets once a week holds onto what you built.

A sample running-priority week:

The hamstring work sits a day after intervals and three days before the long run. If Friday is a hard tempo, keep the split squats light.

How exrsz handles hamstring curls

exrsz builds a periodized plan from your goal, schedule, level and equipment, so a gym with a seated leg curl gets seated curls and a living room gets slider curls. It places hamstring work away from your hard runs in one plan, adapts loads each week to how you actually trained, and reshuffles missed sessions instead of stacking them on the day before your long run.

FAQ

Is the hamstring curl exercise worth doing?

Yes, as an accessory. Hinges like the RDL train the hamstrings at the hip; curls train them at the knee, which hinges barely do. Two or three sets after your main lift is enough for most people.

Is the seated or lying leg curl better?

Seated, if you have the choice. In a 12-week study, seated leg curls increased whole-hamstring volume more than lying curls (+14% vs +9%), likely because the hamstrings work at a longer length when you sit.

Can I do hamstring curls at home?

Yes. Slider or towel curls on a smooth floor, stability-ball curls, Nordic lowers with your ankles anchored, or a band curl all work. Slow lowering keeps them hard without heavy load.

Do Nordic curls reduce hamstring injuries?

Maybe. A 2019 meta-analysis concluded programs including Nordics cut hamstring injuries by up to 51%, but a 2021 reappraisal using only randomized trials called the evidence inconclusive. Do them for strength, not as a guarantee.

How many sets of hamstring curls should I do?

Two to four sets of 8–15 reps, once or twice a week, covers most goals. Runners in a race build can drop to two sets once a week.