Abs exercise
Reverse CrunchHow to do it, with form in numbers
- Main muscles
- Abs
- Equipment
- Bodyweight
- Level
- Beginner
How to do it
How do you do the Reverse Crunch?
- Lie on your back with your arms on the floor beside you, palms down.
- Lift your legs so your knees are over your hips and bent to a right angle.
- Breathe out and curl your hips off the floor, bringing your knees towards your chest.
- Pause, then lower your hips slowly until your knees are back over your hips.
Cues
- Curl your hips towards your ribs.
- Keep the knee bend fixed.
- Lower slowly, no swinging.
Common mistakes
- Swinging your legs to lift: slow down and curl from your stomach.
- Letting your knees drop past your hips: stop when your thighs are upright.
- Pushing hard with your arms: use them only for balance.
Form in detail
What does good form look like?
The version in our demo
Floor reverse crunch from a tabletop leg position, knees held at a right angle, arms on the floor for balance. This is the ACE and physiotherapy version; the feet-on-floor start is a regression and is not shown.
Starting position
Lying on the back on a mat, head and shoulders relaxed on the floor. Legs lifted into tabletop: thighs vertical with the knees directly over the hips, knees bent 90°, shins parallel to the floor, knees and feet together. Pelvis and lower back resting on the mat.
The movement
Curl the pelvis up towards the ribcage so the hips peel off the mat and the knees travel towards the chest, without opening or closing the knee bend. The spine rolls up from the tailbone to about the bottom of the ribs; shoulders, head and arms stay down. Pause briefly, then roll the spine back down slowly until the pelvis rests on the mat and the knees are back over the hips. The knees move in a short arc up and towards the face; the legs never swing.
Breathing
Breathe out as the hips curl up, in as you lower.
Tempo
1.5 s up, 0.5 s pause, 2 s down (4 s).
Form in numbers
What are the angles and distances?
- Start: hip flexion 90°, knee flexion 90° (ACE).
- Knee flexion stays at 90° throughout.
- Shoulder blades, head and arms stay in contact with the mat.
- Return: thighs back to vertical, never past vertical away from the chest.
The targets our 3D demo was built to, from the references below. Bodies differ, so treat the ranges as a guide for your own build.
For coaches
Use this demo in your clients’ programs
The Reverse Crunch is in Trainaq’s exercise library. Add it to a workout, and your client sees this demo in the free Trainaq app above the sets they log.
Sources
