Leg press
Also called 45 degree leg press, sled leg press, machine leg press.
What is a leg press?
The leg press is a machine exercise: seated or lying back against a pad, you push a loaded sled away with both feet, extending your hips and knees together. It trains the quadriceps — mainly the three vasti — along with two muscles that extend the hip and a knee extension machine does not train: the gluteus maximus, and the adductor magnus, whose lower portion extends the thigh. The quadriceps head it does least for is the rectus femoris, the one that also crosses the hip. The calves hold your ankle against the platform; nothing we could read measures whether the leg press grows them. Foot height, stance width and depth are mostly comfort preferences — the evidence that they select a muscle is split, not settled.
How do you perform a leg press?
Set up
- Sit or lie back with your whole back and hips against the pad, not bridged off it.
- Put both feet flat on the platform, roughly hip width apart, toes pointing where your knees will travel.
- Set the safety stops before you push the sled off the catches, not after.
- Foot height, stance width and toe angle are yours to choose; pick what lets you push comfortably with your hips down.
Execution
- Release the catches and take the weight with your legs, not by shoving the seat back.
- Lower under control until your knees are bent as far as you can go with your lower back and hips still flat on the pad.
- Push the platform away by driving through your whole foot.
- Keep the same tempo down as up rather than dropping into the bottom and bouncing out of it.
- Rack the sled on the catches at the end of the set with your legs still bent, not by fully straightening and then reaching for the handle.
Common mistakes
Chasing depth until the pelvis rolls off the pad
Once the hips lift, the lower back rounds under a load that is usually the heaviest thing anyone lifts in a session, and the depth you bought does not grow more quadriceps. Stop where your hips stay down.
Pushing with the heels only, or the toes only
Rolling onto one end of the foot moves the platform contact away from where you can actually brace against it. Push through the whole foot.
Rearranging your feet every set to hit a different muscle
No foot position singles out a muscle reliably enough to programme around. Pick the one that lets you push comfortably with your hips against the pad, and keep it.
Treating the leg press as a complete quadriceps exercise
It trains three of the four quadriceps heads well and appears to do far less for the rectus femoris. Add a knee extension if you want that one covered.
Where it fits in a session
Early in a lower-body session, or after a barbell squat as the main machine work.
The leg press loads heavily with very little skill cost and no balance demand, which is what makes it easy to add sets to. If the rectus femoris matters to you, pair it with a knee extension rather than expecting the press to cover the whole quadriceps.
Muscles worked
- vastus lateralis
- vastus medialis
- vastus intermedius
- gluteus maximus
- adductor magnus
- rectus femoris
- hamstrings
- soleus
Which muscles are on this list comes from one MRI trial rather than from consensus, and the order is not a ranking: read it as the best available measurement of what the movement trains, not as a settled league table. The three vasti and the gluteus maximus grew clearly; the adductor magnus is in the primary list because it grew in the leg press and not in a knee extension trained alongside it, which makes it distinctive to this movement even though the size of the gain was moderate. The rectus femoris is anatomically a quadriceps head and is listed here for that reason, but it was the one head that did not grow, so ranking it with the vasti would misrepresent what was measured. Hamstrings are secondary in the weakest sense: they grew a little, and not measurably more than they did on a knee extension machine. The soleus is listed from anatomy rather than from the trial: pushing through the whole foot with the heels down holds the ankle against the platform, and that is the soleus working. It is a stabiliser here, not a muscle the leg press trains.
What lifters actually do
About seven in ten regular RepCount users have logged a leg press at some point, and it appears in roughly one workout in twelve. When it shows up it is part of a full lower-body session of about six exercises, usually for three or four sets, and it is rarely the whole of what is being trained: leg extensions appear in more than half of leg press sessions, leg curls in about two in five, and calf raises and squats in roughly a quarter each. The pattern in the logs is that lifters treat the leg press as one machine among several on a leg day rather than as the session's main lift.
Most often trained alongside
Share of leg press sessions that also include each exercise.
- Leg extension57.6%
- Leg curl40.3%
- Calf raise27.4%
- Squat25.3%
- Seated calf raise13.7%
Figures come from workouts tracked in RepCount.
Variations
- Single-leg press — One leg at a time on the same machine, which stops the stronger side carrying the set.
- Seated leg press — Upright machine pushing the platform horizontally rather than up an incline.
- Linear leg press — Sled runs on a straight horizontal track instead of an angled one.
- Horizontal leg press — Same horizontal push, named after the machine's travel rather than its seat.
- Vertical leg press — Lying on your back pressing the platform straight upward. A different machine, not a foot-position change.
Frequently asked questions
What muscles does the leg press work?
The quadriceps — chiefly vastus lateralis, vastus medialis and vastus intermedius — along with the gluteus maximus and the adductor magnus. The last of those surprises people, but the lower part of the adductor magnus runs from the pelvis to the femur and extends the thigh, so a machine built around hip extension trains it. In a 12-week MRI trial the leg press grew the gluteus maximus 15.4% and the adductor magnus 6.2%, while a knee extension trained in the same people over the same period changed neither measurably. The soleus is on the secondary list from anatomy, not from the trial: pushing through the whole foot with the heels down holds the ankle against the platform, which is the soleus working. It stabilises the leg press, and nothing we read measures whether the leg press trains it.
Does the leg press work the rectus femoris?
Far less than a knee extension does. In a 12-week MRI trial that had the same people train one leg on each machine, the rectus femoris was the only quadriceps head that did not grow from leg pressing (+1.1%, not statistically significant), against +13.2% on the knee extension leg. The reason is anatomical: it is the only quadriceps head that also crosses the hip, where it acts as a flexor, so a movement that demands hip extension suppresses it. Read the direction rather than the exact figure — this is one small study in untrained people.
Do I still need leg extensions if I do leg presses?
If you care about the rectus femoris, yes, on the evidence we could read. Everything else in the quadriceps grew about as much from leg pressing as from a knee extension in the trial that compared them directly, and the leg press added glute and adductor growth on top. The knee extension's distinct contribution was the rectus femoris.
Does foot placement on the leg press change which muscles you work?
Not reliably, on the current evidence. A systematic review of leg press EMG concluded it remains unclear whether foot height, stance width or foot rotation change muscle activation at all, and that the evidence is not compelling because so few studies agree. Two studies from the review authors found no differences in the quadriceps across stance widths and foot rotations; one older study did find rectus femoris and vastus lateralis more active with low feet, and gluteus maximus with high feet, at heavy loads. Split evidence, so treat foot position as a preference rather than a targeting dial. The illustration on this page shows one foot position, which is not a recommendation.
How far down should you go on the leg press?
As far as you can go without your hips and lower back lifting off the pad. Beyond that it is preference: a study in resistance-trained lifters trained one leg through about 5 to 100 degrees of knee flexion and the other through its full range, four sets to failure twice a week for eight weeks, and quadriceps growth was similar in both. There is no evidence in it that a deeper leg press builds more muscle.
Does the leg press work your hamstrings?
Barely. In that same 12-week MRI trial the hamstrings grew 3.1% from leg pressing and 1.5% from knee extensions, a difference too small to distinguish, and the authors note both are far below the 12% to 19% that studies of leg curls report. Hamstrings belong on the list of muscles that do something during a leg press; they do not belong on a list of muscles it trains.
Should you lock your knees out at the top of a leg press?
The common warning is that full extension shifts load from muscle to joint. The one biomechanical study we could read points the other way on the mechanics: knee forces increased as the knee bent, across every variation tested, and the authors suggested a shallow range for anyone wanting to minimise knee forces. That does not make locking out under a heavy sled a good idea, and we are not telling you to do it — it means the reason usually given for the rule is not what the measurement found.
Is the leg press as good as squats?
No trial we could read compares them for muscle growth, so anyone giving you a confident answer is filling in a gap. What has been measured is activation and joint loading in ten experienced lifters: the squat produced greater quadriceps and hamstring activity than either high or low foot placement on the leg press, and generally greater compressive forces at the knee. Different exercises with different costs, rather than a better and a worse one.
Is the leg press worth doing?
Most regular RepCount users have logged one, though it turns up in only about one workout in twelve. It is rarely the whole session: leg extensions, leg curls, calf raises and squats are what sit beside it. Whether it earns a slot depends on what else is in the session: it adds glute and adductor work a knee extension does not, and it will do little for your rectus femoris.