Sissy Squats and Reverse Nordic Curls: High-Tension Lengthened Quad Training

Sissy squat vs reverse Nordic: both are bodyweight moves that bend the knee deeply while the hip stays open, which puts the rectus femoris (the quad muscle that crosses the hip) at a long length. Neither has been tested head to head for muscle growth, so the honest answer is that they are two different ways to get a similar stimulus. One study even found the reverse Nordic is not more demanding than ordinary single-leg squats.

This guide sits inside our complete lower-body and core training guide. Here we look at what each exercise does, what the evidence supports, how to build up to them, and how to protect your knees.

What do sissy squats and reverse Nordic curls actually do?

The quadriceps has four heads. Three (the vasti) only cross the knee. The rectus femoris crosses the hip as well, so it is stretched most when the hip is extended and the knee is bent. For the anatomy, see our breakdown of the quadriceps heads.

Both exercises create exactly that position.

• Sissy squat: you stand, lift your heels and let your knees drift forward as your torso leans back. Your body forms a line from knees to shoulders.
• Reverse Nordic curl: you kneel and lean back from the knees with a straight body line, lowering as slowly as you can.

The load is your body weight acting at a long lever arm in front of the knee. That is why even a small lean is hard, and why a rail or band makes such a difference.

Is there evidence that they build bigger quads?

Not directly. I could not find a trial that trained either exercise and measured muscle growth, so anything below is indirect.

What we do have is research on training at long muscle lengths with other quad exercises. A systematic review of range of motion studies found that full range and partial range at the lengthened part of the movement produced more growth in the rectus femoris and vastus lateralis than partial range in the shortened part (Kassiano et al., 2023). The authors suggested that quads tend to grow best when trained at longer muscle lengths.

A separate randomized trial in 45 untrained women used the knee extension. Training only the lengthened part (100 to 65 degrees of knee flexion) produced greater growth in certain regions of the rectus femoris and vastus lateralis than other ranges (Pedrosa et al., 2022). Untrained women, one machine exercise, a few regions measured: useful, but it does not transfer neatly to a bodyweight kneeling lean.

An earlier systematic review concluded that full range training seems to favour lower-body hypertrophy compared with partial range, based on six studies (Schoenfeld and Grgic, 2020). If you want the wider concept, we cover it in long muscle length training.

Sissy squat vs reverse Nordic: does either win?

A 2024 cross-sectional study compared the reverse Nordic curl with single-leg squats, Bulgarian squats and forward lunges in 23 healthy volunteers. Eccentric rectus femoris and vastus medialis activation in the reverse Nordic was similar to the squat-based exercises, vastus lateralis activation was lower than the single-leg squat, and knee range of motion was smaller (Pereira et al., 2024).

That cuts against the idea that the reverse Nordic is a special “quad overload” exercise. The study was framed around preventing quad strain injuries, not hypertrophy, and it was a one-session EMG study, not a training trial. But it is a useful reality check.

So how do you choose?

	Sissy squat	Reverse Nordic curl
Balance demand	High	Lower (you are kneeling)
Equipment	Rail or door frame	Pad, band or fixed object
Knee pressure	On the front of the knee	Kneecap pressure on the floor
Easiest regression	Hold rail, shorten range	Lean back less, hold support
Good for	Controlled bodyweight overload	Slow eccentric practice

If balance or heel position makes the sissy squat feel awkward, the reverse Nordic is the easier one to learn. If kneeling bothers your kneecaps, go the other way.

Are sissy squats safe for your knees?

They are demanding, not automatically dangerous. The front of the knee takes a lot of load when the knees travel forward over the toes. In a lab model of 25 healthy young women, squatting with the knees going past the toes produced higher patellofemoral joint stress, reaction force and quadriceps force than squatting with the knees behind the toes (Kernozek et al., 2018). The authors suggest limiting forward knee travel for people with patellofemoral pain.

Two caveats. Those were ordinary squats, not sissy squats, and higher stress in a model does not mean injury in a healthy knee. Tendons and joints adapt to load if you build it gradually. The risk is jumping straight to a deep, fast, unsupported rep.

The patellar tendon is the other thing to respect. Patellar tendinopathy is a painful overload problem at the front of the knee, and the main treatment is progressive strengthening. A 2021 randomized trial of 76 patients found progressive tendon-loading exercise improved the VISA-P score more than eccentric-only therapy at 24 weeks (Breda et al., 2021). A 2025 Cochrane review of seven trials (211 athletes) was cautious, rating most of the evidence low or very low certainty (Lopes et al., 2025). Takeaway: gradual loading is the sound principle, but the tendon research is not strong, and none of it tested sissy squats.

How to progress sissy squats and reverse Nordic curls

This is a coaching framework, not a research protocol.

1. Short range with support. Half depth, hold a rail or door frame. Two sets of 6-8 slow reps.
2. Assisted depth. Go deeper, keeping hand or band support. Control every lowering.
3. Slow lowering, less help. Take 3-4 seconds down and reduce the assistance. Add reps before anything else.
4. Full range. Only when step 3 is easy and pain-free. Add load, such as holding a plate, only if your knees stay calm.

Practical details that matter:

• Keep ribs down and glutes lightly squeezed so you lean as one line instead of folding at the waist.
• On a tiled floor, use a mat for grip and a pad for your knees.
• Warm up with a few light leg extensions or bodyweight squats first.
• Skip the move if you are in a flare of knee pain.

How to program them as a quad finisher

Use them after your main lifts, not before. Heavy squats and leg presses need your legs fresh, and these moves are better as a finisher.

• Frequency: 1-2 times per week.
• Volume: 2-3 sets of 6-12 slow reps.
• Effort: finish a rep or two before your form breaks.
• Placement: after squats or leg press, instead of one set of leg extensions.

Check your weekly leg volume with the training volume calculator, and find a base routine in our leg day plan. If you want a fuller template, see how to organise a complete leg workout.

For the hamstring counterpart of this idea, read our Nordic hamstring curl guide.

Setting these up at home

You do not need a gym for either move. A sturdy door frame, a balcony rail or a heavy wardrobe handle gives you the support for the sissy squat, and a folded yoga mat or a thick cushion works as a kneeling pad. On smooth tiles, check the floor grip first, because a sliding foot or knee at the deepest point is the real hazard.

If you train in a hot room, keep sets shorter and rest a little longer. Slow eccentric reps are tiring, and form is the first thing that slips when you are sweaty and fatigued. A band looped around a fixed anchor gives you adjustable help, so you can reduce the assistance week by week instead of guessing.

Who should skip these, and when to see a doctor

Skip or modify these if you have current kneecap pain, a recent knee injury or surgery, or swelling at the knee. Do not diagnose yourself from a blog post.

See a doctor or physiotherapist if:

• front-of-knee pain lasts more than a couple of weeks
• the knee swells, locks or gives way
• pain wakes you at night
• pain is sharp and is not settling with a lighter version

The bottom line

Sissy squats and reverse Nordic curls are legitimate, low-equipment ways to put the quads under tension at long length. The evidence for long-length training is encouraging, but the evidence for these two exercises specifically is thin, and the one EMG study we have does not make the reverse Nordic look special. Use them as finishers, build range slowly, and keep your knees happy. For the full picture of leg training, return to the complete lower-body guide.