Training guide
A sissy squat bends your knees forward while your body leans back in a straight line from knees to shoulders, so your hips stay straight and the front of your thighs does almost all the work. You don't need a machine: a hand on a wall, a door frame or a rack upright is enough, and a weight plate comes last.
No study has measured the sissy squat itself. What has been measured points one way: leaning back with the knees forward moves the work to the knee, the quad that crosses the hip grows best when it's trained long, and deep, knee-dominant squats are among the heaviest loads on the kneecap of any exercise tested. That makes it a strong quad exercise for healthy knees and a poor choice for sore ones.
This guide shows the bodyweight version step by step on our 3D demo of the weighted one, the steps up to it from the reverse Nordic, how many to do and when to leave it out, with a follow-along progression workout.
Holding a support, rise onto the balls of your feet and lean back in one line from knees to shoulders as your knees bend. Leaning the trunk back and letting the shins travel forward moves the work from the hips to the knee, and the sissy squat takes that to the extreme (our reading).
A hand on a wall or rack upright does the job; a bench or machine pins your feet so you can lean further back. No study compares the versions, and the type of equipment didn't consistently change results across 137 reviews.
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Because your hip stays straight, the rectus femoris, the quad that also crosses the hip, works at a long length. It grew 13% with knee extensions against 1% with the leg press in 12 weeks, grew more with the hip straighter, and didn't grow with squats. No study has measured growth from sissy squats themselves.
The sissy squat itself has never been measured, so this is our reading from related exercises: deep, knee-dominant squats made up the heaviest tier of kneecap load of 35 exercises, at 4.5 to 8.2 times body weight. Healthy knees adapt to deep squats, so build up slowly, and leave it out if the front of your knee hurts.
Start with the heel-elevated deep squat and the reverse Nordic, its kneeling relative, which worked the rectus femoris as hard as single-leg and Bulgarian squats while lowering. Then sissy squats holding a support part way, then the full range, then with a plate.
With a plate, 2 to 3 sets of 6 to 10, stopping 2 or 3 reps short of failure (its move page's dose). With body weight, build from 2 sets of 5 to 8 part way to 3 sets of 10 to 12 through the full range (our editorial starting point). Once or twice a week, after your main leg work.
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Holding a support with one hand, feet about shoulder-width apart, you rise onto the balls of your feet and bend your knees forward while your body leans back in one straight line from knees to shoulders, so your hips don't bend. You lower slowly to about a right angle at the knee, deeper as you progress, then straighten your knees to come back up. It's the opposite of a hip hinge: everything happens at the knee and ankle.
In 100 people doing bodyweight squats, a more forward shin moved the balance of work from the hip towards the knee, and more trunk lean moved it back, trunk lean having the larger effect. In 7 men, holding the knees back in a barbell squat cut the knee's load by about a fifth and raised the hip's about tenfold. A sissy squat does the opposite of both: the trunk leans back and the shins tip far forward, so the knee does almost all the work (our reading).
The quadriceps, including the rectus femoris while it's stretched across the hip. Your abs and the front of your hips hold the straight line, and your calves hold you on your toes. In trials, single-joint knee extension grew the rectus femoris far more than the leg press, and more with the hip straighter, and across 11 studies training at long muscle lengths tended to favour growth.
None of these trials used the sissy squat, and muscle activity in a few reps shows effort, not what a muscle will build.
Holding a support is the usual start. A sissy squat bench or machine locks your feet and calves so you can lean back without falling. A plate held at your chest adds load, which is what our 3D demo shows. Coaches also use a hack squat platform or a Smith machine, which we have no demo of.
The reverse Nordic is the kneeling relative, and the heel-elevated deep squat, a deep squat with the heels raised and the trunk fairly upright, is a gentler knees-forward squat. We have no separate demo of the bodyweight sissy squat, so the steps below use the weighted demo and leave the plate until last.
A comfortable heel-elevated deep squat, controlled reverse Nordics in a small range, and no pain at the front of the knee. The weighted version's move page asks for a bodyweight sissy squat or reverse Nordic through the full range before you add the plate.
The load on your knee rises with your body weight, your depth and how far you lean back (our reading of the load studies). Kneecap or tendon pain, knee arthritis and a growing knee in a teenager all call for the gentler options in this guide.
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Nobody knows for sure where it comes from. One equipment seller's story about King Sisyphus has no source.
From our weighted sissy squat move page, taught without the plate first, as its own cue says: start with body weight before adding the plate. We have no separate bodyweight demo, so the figure holds the plate; leave it out until the last step of the ladder.
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The movement on the figure: Weighted sissy squat
Easiest first: heel-elevated deep squats, 2 sets of 6 to 8, and reverse Nordics, 2 sets of 3 to 5 in a small range (our knee strengthening workout); the arms-overhead reverse Nordic, 2 sets of 3 to 5, as a harder side step (our editorial starting point); then sissy squats holding a support with no plate, 2 sets of 5 to 8 part way, building to 3 sets of 10 to 12 through the full range (our editorial starting point); and finally with a plate, 2 to 3 sets of 6 to 10, stopping 2 or 3 reps short of failure (its move page's dose).
No study compares a sissy squat bench, a machine and the free version. Across 137 reviews, the type of equipment didn't consistently change strength or muscle gains. A bench lets you lean further back with less balance, and some people like that; a support you hold is enough to learn it and to build it up.
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Coaches also do sissy squats on a hack squat platform or in a Smith machine, with the heels up and the knees travelling far forward. We have no demo of those, and the same rules apply: build the depth slowly, and stop if the front of your knee hurts.
No study has measured the sissy squat's muscle activity, muscle growth or knee load. The notes below are about its nearest relatives, and our reading of them.
In 100 adults doing bodyweight squats, a more forward shin lowered the hip's share of the work and more trunk lean raised it. Holding the knees back moved the load from the knee (150 to 117 newton metres) to the hip (28 to 303) in 7 men. A biomechanical review sets out how stance, trunk and shin position change a squat's joint loads.
In 17 untrained adults, knee extensions grew the rectus femoris 13.2% in 12 weeks against 1.1% with the leg press, with similar growth in the other quads. In 22 untrained men, a leg extension with the hip less bent grew it more over 10 weeks, and in 17 men full and half squats didn't grow it at all. Across 11 studies, training at long muscle lengths tended to favour growth.
In 23 adults, the reverse Nordic worked the rectus femoris and inner quad as hard while lowering as bodyweight single-leg squats, Bulgarian squats and forward lunges, through less knee bend. Eight weeks of it lengthened the rectus femoris fibres and thickened the muscle in 26 adults, changes that reversed 4 weeks after they stopped (there was no separate control group), and improved sprinting, change of direction and jumps in 27 youth karate athletes against karate training alone.
The sissy squat itself has never been measured. In models of 20 healthy adults across 35 exercises, the heaviest tier of load on the joint behind the kneecap was made up of deep, knee-dominant squats: the single-leg decline squat (peaks of 8.2 times body weight), the full single-leg squat (6.9) and a 3-second Spanish squat hold (4.5, with the largest load over time). The single-leg decline squat also loaded the patellar tendon, below the kneecap, the most. Our reading is that a sissy squat belongs with them.
A review of over 164 articles found fears that deep squats harm healthy knees unfounded, and in one exploratory trial in 57 young adults, letting the knees travel forward in bodyweight squats caused no problems over 6 weeks. There are no injury data for the sissy squat.
Stress behind the kneecap was lowest in leg extensions from 90 to 45 degrees of knee bend and in squats from 45 degrees to straight, in 10 adults. Use those ranges while your kneecap is sore, and see our knee pain when squatting guide. With pain at one point just below the kneecap, our jumper's knee guide starts with Spanish squat holds.
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Start with 2 sets of 5 to 8 through part of the range, holding a support, and build to 3 sets of 10 to 12 through the full range before adding a plate (our editorial starting point, following our plans' rule: add reps, then slow the lowering, then move to the harder option).
2 to 3 sets of 6 to 10, stopping with 2 or 3 reps in reserve (its move page's dose). We keep 2 or 3 in reserve on every set, rather than taking the last set closer to failure as our plans allow for small moves, because the knee carries the load (our view).
60 to 90 seconds between sets and a controlled 2 to 3 seconds down, once or twice a week after your squats or lunges (our editorial starting point, as our leg extension guide places its single-joint work). Count the sets towards the 10 or so hard sets a week that build the quadriceps.
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In your first two weeks, stop every set with 3 or 4 reps to spare, as our plans advise. Going to failure adds little muscle, and people underestimate the reps they have left by about 1.
Expect sore front thighs after the first sessions. It fades as you repeat the move, as our plans note.
It turns into an ordinary squat. Squeeze your glutes and keep the line from your knees to your shoulders.
Lower over 2 to 3 seconds.
Add depth over weeks. Kneecap pain that lingers into the next day means you went too deep or did too much, as our heel-elevated deep squat's move page warns.
Lean back only as far as you can come back from, keep hold of the support, and don't arch your lower back.
Coaches warn that falling backwards is a commoner mishap than a knee injury, so keep a hand on the support until the full range is easy.
Keep them over your middle toes.
Spanish squat holds, 4 to 5 holds of 30 to 45 seconds (its move page's dose), for tendon pain below the kneecap; leg extensions, 2 to 3 sets of 10 to 15 (our leg extension guide), one leg at a time, 2 to 3 sets of 8 to 12 each leg, or on a chair, 3 sets of 10 to 15 each leg (their move pages' doses); Patrick step-downs, 8 slow reps each side (our knee strengthening workout); ATG split squats, a deep split squat with the front knee far forward, 2 sets of 5 each side (our splits routine); and a standing quad stretch, 20 to 30 seconds, 2 to 4 times each side, and knee-to-wall rocks, 10 a side (their move pages' doses).
3D demoSpanish squat (band squat hold)Intermediate · A band + An anchor point
3D demoLeg extensionBeginner · Strength machine
3D demoSingle-leg leg extensionBeginner · Strength machine
3D demoSeated knee extension (chair)Beginner · A bench or box + Something with weight
3D demoPatrick step-downIntermediate · A step
3D demoATG split squatAdvanced · No equipment
3D demoStanding quad stretchBeginner · A wall
3D demoKnee-to-wall ankle rockBeginner · A wallOur sissy squat progression follows the ladder above. The knee strengthening workout has the reverse Nordic and heel-elevated squat, and the machine and gym leg days have leg extensions, after which a few sissy squat sets fit.
Build to a sissy squat: knee and ankle prep, the reverse Nordic, sissy squats holding a support, then the weighted version, with a single-leg step-down.
25 minIntermediate8 movesA wall, A stepA 25-minute session for knees that don't currently hurt: thigh and hamstring strength, single-leg control, then an optional full-range block with knees over toes.
25 minBeginner13 movesA bench or box, A wallA 45-minute leg day on machines only: the leg press, then leg extensions and seated leg curls for the muscles it misses, hip abduction and calf presses.
45 minBeginner10 movesCardio machine, Strength machineA gym leg day: back squats, leg press, leg curls, Bulgarian split squats, leg extensions and calf raises.
55 minIntermediate9 movesA wall, A barbellBuild to a pistol squat: ankle and balance prep, step-downs, skater squats, box and counterweight pistols, then the full one-leg squat.
25 minIntermediate8 movesA wall, A stepThe leg day of our push, pull, legs plan uses leg extensions; once the bodyweight sissy squat is easy, 2 sets after them fit the plan (our suggestion).
Swap it for leg extensions between 90 and 45 degrees of knee bend, or squats to about 45 degrees, where kneecap stress was lowest. Keep pain at 0 to 2 out of 10, or up to 5 if it has settled by the next morning, as our knee pain when squatting guide advises.
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Keep tendon pain at 3 out of 10 or less and settled by the next morning, and use our jumper's knee or quadriceps tendinopathy guide's plan, which starts with Spanish squat holds.
If you take steroid tablets or have steroid injections, use anabolic steroids, have kidney disease, gout, rheumatoid arthritis, lupus or diabetes, or have recently taken a fluoroquinolone antibiotic, tell your GP or physiotherapist and build up more gradually, as our knee pain when squatting guide advises.
A teenager with pain at a bump just below the kneecap, or at its lower tip, should follow our Osgood-Schlatter or Sinding-Larsen-Johansson guide instead, keeping pain at 2 out of 10 or less.
Follow your surgical or physiotherapy team's limits.
Always hold a support (our suggestion).
If you get chest pain or pressure, feel faint or dizzy, are unusually breathless, or your heart races or beats irregularly during exercise, as our plans advise. The American Heart Association says these need immediate medical evaluation.
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For chest pain that comes on suddenly and doesn't go away, or spreads to your arms, neck, jaw, stomach or back; a sudden, extremely painful headache while straining; someone who faints while exercising; or palpitations that don't go away, or come with chest pain, breathlessness or feeling faint. Don't drive yourself to A&E.
If you haven't exercised for some time or have a medical condition, speak to your GP first, as the NHS advises. Get advice before hard straining work if your blood pressure is uncontrolled, or you have heart disease or chest pain when you're active, a pacemaker or defibrillator, diabetic eye disease, glaucoma, a hernia, recent eye or tummy surgery, or you're pregnant, as our breathing guide lists.
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A pop or tearing feeling at the front of the knee after a fall, stumble, jump, landing or a heavy squat, then you can't straighten the knee or lift the straight leg off the bed, there's a dent above or below the kneecap, or the kneecap sits higher or lower than on the other side. Go to A&E or an urgent treatment centre, or get help from NHS 111. A torn quadriceps or patellar tendon does best when it's repaired soon, as our knee pain when squatting guide says.
Get advice from NHS 111 if your knee is very painful, you can't move it or put weight on it, it's badly swollen or has changed shape, it locks, gives way or clicks painfully, or it's hot and red and you have a high temperature. See a GP if knee pain doesn't improve within a few weeks. In the US, use urgent care.
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Call 999 or go to A&E if you heard a crack, the knee has changed shape or points at an odd angle, the leg below it is numb or tingling, or the skin has changed colour or feels cold. Get help from NHS 111 if it's very painful or getting worse, badly swollen or bruised, or you can't put weight on it or walk more than a few steps.
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See a GP if you think you have a hernia. Get help from NHS 111 if you have a hernia and pain in or around it, a bloated tummy, sickness, vomiting blood or vomit that looks like coffee grounds, constipation, a high temperature or sudden confusion. Call 999 or go to A&E for a femoral hernia (a lump at the top of the thigh) with very bad tummy pain, sickness, being unable to fart or poo, a high temperature or sudden confusion.
There are no injury data. The kneecap and tendon loads of the closest measured exercises are among the highest of 35 tested, and healthy knees adapt to deep, loaded bending. So it suits healthy knees built up gradually, not sore ones.
No study compares the versions, the type of equipment didn't consistently change results across 137 reviews, and our move page teaches it with one hand on a support.
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Some sellers of sissy squat benches say so. The load evidence says build up slowly, and a pop at the front of the knee is a same-day problem.
No study has measured where sissy squats build muscle. In the closest trial, knee extensions grew the three vasti (the inner, outer and middle quads) about as much as the leg press (5.0 to 7.2% against 4.4 to 6.2%) and the rectus femoris more. No exercise can promise a shape.
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In 12 weeks, the whole quadriceps grew about the same with knee extensions and leg presses (7.1% against 4.9%, not a meaningful difference), and only the leg press grew the glutes and the big adductor. Squats and sissy squats do different jobs; use both if you like.
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A sissy squat is built on the knees travelling far past the toes. In ordinary squats it's normal, and holding the knees back gave no advantage in one exploratory trial.
A squat where your hips stay straight: holding a support, you rise onto the balls of your feet, push your knees forward and lean your body back in one line from knees to shoulders, then straighten your knees to come up. It puts almost all the work on the front of your thighs.
Hold a wall, door frame or rack upright with one hand, feet about shoulder-width apart, and go only as deep as you can come back from. Start part way down and build the depth over weeks; a plate at your chest comes last.
The quadriceps, including the rectus femoris while it's stretched across the hip; your abs and hip flexors hold the straight line. The rectus femoris grew most with knee extensions done with the hip straighter, and barely at all with squats, but no study has measured sissy squats themselves.
There are no injury data. Deep, knee-dominant squats like it put the highest kneecap and patellar tendon loads of 35 exercises measured, and healthy knees adapt to deep, loaded bending. Build up slowly, and leave them out if the front of your knee hurts.
Both train the quads with the hip fairly straight. The leg extension is easier to load and to stop at a comfortable depth, and it has the growth trials; the sissy squat needs no machine but more balance and a lot of knee bend. Our leg extension guide covers the machine.
The reverse Nordic is its kneeling relative and the easier step. It worked the rectus femoris and inner quad as hard as bodyweight single-leg and split squats through less knee bend, and 8 weeks of it lengthened the rectus femoris fibres. Learn it first.
With body weight, start with 2 sets of 5 to 8 through part of the range and build to 3 sets of 10 to 12. With a plate, 2 to 3 sets of 6 to 10, stopping 2 or 3 reps short of failure, once or twice a week.
Not while your kneecap hurts. Leg extensions between about 90 and 45 degrees of knee bend, where kneecap stress was lowest, and the plans in our knee pain guides are better. With pain at one point just below the kneecap, our jumper's knee guide uses Spanish squat holds.
They lock your feet so you can lean back further with less balance, which some people like. No study compares them with the free version, and the type of equipment didn't consistently change results across 137 reviews.
Nobody knows for sure. One equipment seller tells a story about King Sisyphus without a source, and we found no reliable history.
Start lower down the ladder: the heel-elevated deep squat, then the reverse Nordic, then sissy squats holding a support through part of the range. Our sissy squat progression workout sets out the steps.
You're leaning back further than your strength can bring you up from. Keep hold of the support, lean back less, and squeeze your glutes so your hips stay straight.
Exercise education, not a personal prescription, and clinical review of these guides is pending. Check with a GP before starting hard training if you have a heart condition, chest pain, dizziness or breathlessness when active, and stop for sharp or increasing pain. Health disclaimer.
