Medicine Ball Straight Arm Crunch — how to, muscles worked, alternatives

How to do the Medicine Ball Straight Arm Crunch

Lie on your back, knees bent, holding a medicine ball above your chest.
Curl your head and shoulders up, pushing the ball toward the ceiling.
Keep your arms straight and your lower back on the floor.
Slowly lower back down until your upper back touches the floor again.

Full technique — 7 steps

Lie on your back with knees bent and feet flat on the floor.
Hold a medicine ball with both hands, arms straight above your chest.
Press your lower back into the floor and keep your ribs pulled down.
Curl your head, shoulders, and upper back off the floor by shortening your abs.
Push the ball toward the ceiling as you rise, keeping your arms straight.
Lift until your shoulder blades clear the floor without turning it into a sit-up.
Lower your upper back down until your shoulder blades return to the floor.

Common mistakes

Bending the elbows to move the ball
Letting the ball drift behind your head
Turning reps into sit-ups
Lower back arching off floor
Swinging up with momentum

Form cues

Keep arms straight
Reach toward the ceiling
Keep low back down
Lift shoulder blades only
Exhale into the crunch

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.

This exercise Medicine Ball Straight Arm Crunch Beginner
Harder Medicine Ball Toe Touch Crunch Beginner
Harder Ab Wheel Half Rollout 40% of bodyweight

Quick answers

What muscles does the Medicine Ball Straight Arm Crunch work?

Primary: Abs 10/10. Also works: Obliques 5/10.

When should I do the Medicine Ball Straight 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 Medicine Ball Straight Arm Crunch?

Strength: 3–4 sets of 8–12 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 Medicine Ball Straight Arm Crunch?

No equipment: Seated Leg Raise, Ab Wheel Straight Arm Crunch. Dumbbells: Dumbbell Decline Sit-Up, Dumbbell Straight Arm Crunch. Resistance bands: Lying Resistance Band Crunch, Lying Resistance Band Knee Tuck. Suspension trainer: Suspension Trainer Hanging Knee Raise, Suspension Trainer Hanging Leg Raise.