What muscles do crunches on an exercise ball work?
Because of its ability to target the entire core, the Swiss-ball crunch should be a staple in your workout. The exercise primarily works the rectus abdominis, or six-pack muscles, and the transverse abdominis. But when performed properly, it also calls on muscles that stabilize the hips and lower back.
How to do a proper ball crunch?
Are Bosu ball crunches effective?
Crunches on a stability ball were as effective as traditional crunches but not significantly better at targeting the rectus abdominis. For the external obliques, crunches on a stability ball DID activate these muscles more.