The reverse Nordic curl is a kneeling quadriceps exercise. You kneel upright, keep your hips extended, lean back by bending only at the knees, then straighten them to come back up. It is also called a natural leg extension.
Brolic lists it as Reverse Nordic Curl, a bodyweight exercise logged in reps with no load field. The hamstring exercise is a separate entry, Nordic Curl (Bodyweight). The lean can be shallow, deep, assisted or weighted, so the guide also covers what to write beside the reps.
Muscles worked
Brolic tags the quadriceps as primary and the abdominals as secondary. Only the knees move: the quadriceps control the bend as you lean back and straighten the knees to bring you up, while the abdominals and glutes hold the trunk and hips in line.
One of the four quadriceps, the rectus femoris, also crosses the hip. In one study, 26 people did eight weeks of eccentric (lowering-phase) training with the exercise, and ultrasound of that muscle showed greater fascicle length, thickness, pennation angle and cross-sectional area; four weeks without training reduced all four. A second study, of 23 volunteers, found quadriceps activity in the lowering phase no higher than in bodyweight single-leg squats, Bulgarian squats or forward lunges, with less knee bend.
Set it up
- Check that you can kneel. Marc Surdyka, the physical therapist behind E3 Rehab’s guide, tests this by sitting back on the heels. If that, or weight on the tops of the feet, hurts, work on it first.
- Kneel on a pad, pillow or towel; something soft under the ankles is optional.
- Set the knees about hip-width apart or wider.
- Tuck the toes or lay the feet flat, whichever is comfortable.
- Put a bench, sofa or stack of pads behind you as a safety net and a fixed mark for how far you leaned.
Perform the curl
Squeeze your glutes and brace your abs, hands by your sides, with knees, hips and shoulders in a straight line.
Lean back slowly, bending only at the knees. Meghan Callaway asks for three to five seconds on the way down. Do not fold at the hips or arch the lower back to get lower.
Stop where you can still control it. Surdyka’s rule is not to trade technique for a little more range.
Straighten the knees to come back up, holding the same line.
Start with few reps and a short lean. A study of youth karate athletes progressed from two to four sets of 6 to 10, twice a week, a starting point for learning the movement rather than a target.
Shorten or assist the range
While you learn it:
- Lean less, stopping at the support behind you.
- Hold your arms straight out in front, Surdyka’s easier arm position.
- Use a band. Callaway fastens it to something secure and holds it or loops it around the torso, using as little help as possible.
- Lower only. Lean back under control, catch yourself with your hands and reset upright.
To make it harder, lean further first, as the karate study did. Surdyka then raises the arms overhead; Callaway adds band resistance, a weight at the chest or a loaded backpack once the bodyweight version is solid.
How it differs from a Nordic curl and a sissy squat
| Reverse Nordic curl | Nordic curl | Sissy squat | |
|---|---|---|---|
| Position | Kneeling | Kneeling, feet anchored | Standing, heels lifting |
| Movement | Lean back | Lower forward | Knees forward, torso back |
| Muscles | Quadriceps | Hamstrings | Quadriceps |
The sissy squat also keeps the hips extended while the knees bend, and Tony Gentilcore likens the two, but it is done standing on the balls of the feet, so balance is part of it. No trial we found compares them; the table ranks nothing.
Logging
Brolic logs Reverse Nordic Curl in reps with no load field, so the entry cannot tell a shallow set from a deep one. Beside the reps, record how far you leaned (a bench of known height, or the floor), any assistance (band, arms forward, lowering only) and any added weight or band resistance. The free workout log has room for those notes, and the weekly set tally shows how these sets add to your quadriceps work.
Common questions
How far should I lean? As far as you can control with the hips extended. Surdyka treats touching the back to the floor as a goal some people train for, not a requirement.
Does it prevent quad strains? No study we found tested that; the 2019 authors say only that their findings may matter for injury prevention and rehabilitation.
Can it replace squats or leg extensions? Nothing establishes that. Surdyka calls it a viable accessory that probably should not be your primary quad exercise.
My knees hurt. Stop the set. Next time add padding and shorten the lean. If it still hurts, pick another exercise; Surdyka names the seated leg extension as the simplest. Do not work through pain.
Sources and method
- E3 Rehab: reverse Nordics guide (2023) and earlier article (2020), by Marc Surdyka, DPT — setup, range, support, arm and foot positions, alternatives.
- Meghan Callaway: regressions and progressions (2022) and five variations (2020) — lowering count, band assistance, added resistance.
- Tony Gentilcore: Reverse Nordic Curl (2019) — the sissy squat comparison.
- Alonso-Fernandez et al. (2019) and Pereira et al. (2024) — rectus femoris structure after training; muscle activity against squat-based exercises. Abstracts only.
- Bouguezzi et al. (2024) — how the exercise was instructed and progressed in youth karate athletes.
- E3 Rehab: Nordic hamstring curls and BarBend: sissy squat — the table’s other two exercises.
- Brolic catalog version 2026-09-22.1 — names, logging mode and muscle tags.
Ranges, tempos and rep counts are starting points from the coaches and studies cited, not optima established by a trial. A PubMed search on October 5, 2026 found no trial comparing the reverse Nordic curl with a sissy squat or leg extension, and none with injury as its outcome.
