The study found that crunches performed on a stability ball (a.k.a. fitness ball or Balance Ball) boosted activation, or flexing, of abdominal muscles by 24 to 38 percent over crunches done without a ball .
The study found that crunches performed on a stability ball (a.k.a. fitness ball or Balance Ball) boosted activation, or flexing, of abdominal muscles by 24 to 38 percent over crunches done without a ball .