Core

Reverse Crunch

Instead of lifting your torso, you bring your knees to your chest and roll your pelvis up: ab work without neck strain.

Also known as: lower ab crunch

Level: Intermediate
Equipment: Bodyweight
Type: Isolation

Movement

Muscles worked

Reverse Crunch muscle map: abs, hip flexors, obliques and deep core highlighted on the front and back of the body

How to do it

Lie on your back with your legs bent to 90 degrees and arms by your sides.
Bring your knees toward your chest, rolling your pelvis off the floor.
Squeeze your abs at the top for a second.
Lower slowly until your pelvis is back down.

Form cues

The key movement is lifting your pelvis.
No leg swing.
Arms on the floor for balance, not pushing.

Common mistakes

Swinging your legs: momentum replaces your abs.
Not lifting your pelvis: only your hip flexors work.
Dropping on the way down: control it.

Sets and reps

3 sets of 10-15 reps with 45-60 seconds of rest.

Variations

Same movement, different equipment. Pick based on what you have and what you want from reverse crunches.

Cocoons
Bring your arms and legs in toward the middle together.
Bodyweight · Intermediate
How to do it
1. Lie face-up on the floor with arms extended overhead and legs extended, hovering slightly off the floor.
2. Simultaneously tuck the knees toward the chest and sweep the arms forward into a crunch.
3. Try to touch the hands to the shins at the top.
4. Reverse the motion smoothly, re-extending arms and legs back to the hover.
Primary
Abs
Secondary
Hip Flexors, Obliques
Bench leg pull-in
Sitting on a bench edge, pull your knees in.
Bodyweight · Beginner
How to do it
1. Lie on your back on a flat bench and grip the sides behind your head for support.
2. Extend your legs straight out with heels just above the bench surface.
3. Pull your knees toward your chest, lifting the hips slightly off the bench.
4. Extend the legs back out under control without letting the heels touch the bench.
Primary
Abs
Secondary
Hip Flexors, Obliques
Stability ball knee tuck
In a plank with feet on the ball, pull your knees to your chest.
Stability Ball · Intermediate
How to do it
1. Start in a high plank with both shins or the tops of the feet on top of a stability ball.
2. Hands are under the shoulders, body in a straight line.
3. Brace the core and pull the ball toward the chest by tucking the knees in.
4. Roll it back out by extending the legs fully back to the plank position.
Primary
Abs
Secondary
Front Delts, Hip Flexors, Obliques, Serratus
Stability ball pike
From a plank, pike your hips up with straight legs.
Stability Ball · Advanced
How to do it
1. Place the shins on a stability ball and hands on the floor in a high plank.
2. Brace the core and keep the legs straight.
3. Pike the hips up, rolling the ball toward the chest as the body forms an inverted V.
4. Pause briefly at the top.
5. Roll the ball back out to the starting plank.
Primary
Obliques, Abs
Secondary
Front Delts, Hip Flexors, Serratus