Long Arm Crunch — how to, muscles worked, alternatives

How to do the Long Arm Crunch

Lie on your back, knees bent, arms straight overhead beside your ears.
Press your lower back into the floor and keep your ribs pulled down.
Curl up until your torso is about 45 degrees, arms following.
Slowly lower back down until your upper back touches the floor again.

Full technique — 6 steps

Lie on your back with knees bent and feet flat on the floor.
Extend both arms straight overhead beside your ears, one hand over the other.
Press your lower back into the floor and keep your ribs pulled down.
Curl your head, shoulders, and upper back off the floor, keeping your arms in line with your torso.
Rise until your torso is about 45 degrees from the floor, with your hips and feet still down.
Lower your torso slowly until your upper back and arms return to the floor.

Common mistakes

Swinging arms for momentum
Letting the arms drop forward
Lower back arching off floor
Lifting the feet off the floor
Dropping into the next rep

Form cues

Keep arms by ears
Curl ribs toward pelvis
Lift with abs first
Curl, don't yank up
Keep feet planted

Substitutes by equipment

Same muscles, same movement — pick the version you have the gear for.

Where to start and where to go next

Same muscles, same movement. Too hard for now — step down; once it gets easy — step up.

Easier Ab Wheel Straight Arm Crunch 15% of bodyweight
Easier Bench Knee Tuck 20% of bodyweight
This exercise Long Arm Crunch 25% of bodyweight
Harder Ab Wheel Pass Crunch 30% of bodyweight
Harder Ab Wheel Half Rollout 40% of bodyweight

Too hard for now? Start with the Bench Knee Tuck.

Quick answers

What muscles does the Long Arm Crunch work?

Primary: Abs 9/10. Also works: Obliques 6/10.

When should I do the Long Arm Crunch in a workout?

Finisher. Goes last, once the heavy work is done. ≈ 5 min with rest.

How many sets and reps of the Long Arm Crunch?

Strength: 3 sets of 10–12 reps, rest 1 min 15 s, 2–3 reps in reserve. Muscle growth: 3–4 sets of 12–20 reps, rest 1 min, 2–3 reps in reserve. Endurance: 2–3 sets of 20–30 reps, rest 45 s, 3–4 reps in reserve.

What can I do instead of the Long Arm Crunch?

Resistance bands: Kneeling Resistance Band Crunch, Resistance Band Decline Sit-Up. Suspension trainer: Suspension Trainer Hanging Leg Raise, Suspension Trainer Hanging Knee Raise. Dumbbells: Dumbbell Decline Sit-Up, Dumbbell Straight Arm Crunch. Medicine ball: Medicine Ball Toe Touch Crunch, Medicine Ball Straight Arm Crunch.