Stability Ball Crunch

Why it matters

Lying back on a stability ball allows a deeper stretch at the bottom of the crunch than the floor allows, increasing the range of motion the abs work through. The unstable surface also adds a balance demand that a floor crunch doesn't include.

How to do it

1. Sit on the ball and walk your feet forward. Lie back until your lower back is supported by the ball, knees bent, feet flat on the floor.
2. Place your hands lightly behind your head. Curl your shoulders up off the ball, same motion as a standard crunch.
3. Stop a few inches up. Same short-range principle as a floor crunch — there's no need to sit up fully.
4. Lower with control back onto the ball. Let your back settle back into the stretched position before the next rep.

Common mistakes

• Using an unstable or poorly inflated ball. Make sure the ball is appropriately sized and inflated for safe, stable use.
• Pulling on the neck with the hands. Same principle as any crunch variation — hands should support, not pull.
• Letting the hips shift excessively to maintain balance. Some core engagement to stay balanced is part of the exercise, but excessive shifting suggests the ball size or position needs adjustment.
• Rushing through reps. A controlled tempo lets you both balance and engage the abs effectively.

Sets & reps by level