Exercise Ball Crunch
The exercise ball crunch takes the standard floor crunch and moves it onto a stability ball, with your lower and mid back supported by the ball's curve. That support lets your torso extend slightly before each curl, giving your abs a longer range of motion to work through than a flat floor crunch allows.
Why it works
On the floor, a crunch's range is limited because your back is already flat against the ground at the bottom of the movement. The ball's curve lets your spine extend back slightly before you curl forward, so your abs get to work through a longer stretch-to-contraction range. The ball's instability also asks your deep core to work harder just to keep you balanced on it, on top of the crunching motion itself.
Set up
- Sit on the ball and walk your feet forward until your lower and mid back rest on its curve.
- Plant your feet flat on the floor, shoulder-width apart, for a stable base.
- Cross your arms over your chest or rest your fingertips lightly behind your head.
How to do it
- Curl your torso up and forward by contracting your abs.
- Rise until your shoulder blades lift clearly off the ball.
- Pause briefly at the top of the curl.
- Lower back down with control until your back settles onto the ball's curve again.
- Repeat for the set without bouncing off the ball between reps.
Form cues
- Curl from your abs, keep your neck relaxed.
- Keep your feet flat and firmly planted throughout.
- Lower with control, don't just drop back onto the ball.
- Exhale as you curl up to fully engage your abs.
Breathing: Exhale as you curl up and contract, inhale as you lower back down over the ball.
Common mistakes
Pulling on the neck with the hands to help the curl.
Fix: Rest your fingertips lightly behind your head for support only, and let your abs initiate the lift.
Letting the feet shift or the ball roll during the set, breaking balance.
Fix: Plant your feet a bit wider and keep steady pressure through them to anchor the ball in place.
Dropping back onto the ball quickly instead of lowering with control.
Fix: Slow the lowering phase down; the negative portion of the curl still builds strength.
How to program it
- 3 sets of 12 to 15 reps is a good starting range, since this is a bodyweight isolation move with a light overall fatigue cost.
- 2 to 3 sessions a week fits well as part of a core routine, and it pairs naturally with a lower-ab move like a reverse crunch.
- Once the extra range and balance demand feel easy, the abs wheel rollout is a natural next step for more core challenge.
Safety notes
- Use a ball sized so your knees sit near a 90 degree angle when your feet are flat on the floor.
- Keep the ball on a non-slip surface or against a wall behind you if balance feels shaky at first.
Exercise profile
- Force
- Pull
- Mechanics
- Isolation
- Category
- Strength
Frequently asked questions
How many reps of exercise ball crunches should I do?
3 sets of 12 to 15 reps is a solid starting point for most people, since it's a bodyweight movement you can progress by slowing the tempo or adding reps.
What size stability ball should I use for ball crunches?
Pick a ball that lets your knees sit at roughly a 90 degree angle when your feet are flat on the floor and your back rests on the ball.
Exercise ball crunch vs regular floor crunch, which is better?
The ball version gives your torso a longer range of motion, since your spine can extend back slightly before you curl, and adds a balance challenge. The floor version needs no equipment and is easier to control while you're still learning the movement.