Core

Crunch

Curling your torso up while lying on your back: the classic rectus abdominis exercise, with no equipment.

Also known as: ab crunch, floor crunch

Level: Beginner
Equipment: Bodyweight
Type: Isolation

Movement

Muscles worked

Crunch muscle map: abs and obliques highlighted on the front and back of the body

How to do it

Lie on your back with your knees bent and feet flat.
Place your hands at your temples or crossed over your chest.
Breathe out and curl your torso up, lifting your shoulders off the floor.
Hold for a second and lower slowly.

Form cues

Think about bringing your ribs toward your pelvis.
Your lower back stays on the floor.
Don't pull on your neck with your hands.

Common mistakes

Pulling your head with your hands: it strains your neck. Your hands just rest there.
Coming all the way up: that's a sit-up and works your hip flexors more.
Going fast with momentum: your abs do less.

Sets and reps

3 sets of 12-20 reps with 45-60 seconds of rest. When they get easy, hold a plate on your chest.

Variations

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

Decline crunch
More range and more load for your abs.
Bodyweight · Intermediate
How to do it
1. Secure your feet at the top of a decline bench.
2. Lie back with hands crossed on your chest or behind your head.
3. Crunch up by flexing your spine toward your knees.
4. Squeeze your abs at the top.
5. Lower under control and repeat.
Primary
Abs
Secondary
Hip Flexors, Obliques
Weighted wall crunch
Feet on the wall and a plate on your chest.
Weight Plate · Intermediate
How to do it
1. Lie on your back and park your legs so your hips cannot help: brace your feet against a wall or a box, or hold your legs up with the knees bent.
2. Hold a weight against your chest with both hands -- a plate, a dumbbell, or a kettlebell all work.
3. Crunch up, lifting your shoulder blades off the floor.
4. Lower with control.
Primary
Abs
Secondary
Obliques
Cross-body crunch
Elbow toward the opposite knee: adds obliques.
Bodyweight · Beginner
How to do it
1. Lie face-up on the floor with knees bent and hands lightly behind the ears.
2. Crunch up and rotate, bringing the right elbow toward the left knee as the knee draws up.
3. Return to the starting position under control.
Primary
Obliques
Secondary
Abs
Machine crunch
Seated against resistance: easy to load.
Ab Crunch Machine · Beginner
How to do it
1. Sit in the abdominal crunch machine and grip the handles.
2. Position the chest pad against your upper body.
3. Contract your abs to crunch your torso forward and down.
4. Squeeze at the bottom of the movement.
5. Return to the starting position with control.
Primary
Abs
Secondary
Obliques, Deep Core