Lay your belly on a ball, and find stability by spreading your legs wide and planting your toes on the floor.
Bring your arms in front of your ball, make fists, and point your thumbs out to the sides.
Take a breath in, and as you exhale, raise your upper torso as much as you can, so your chest comes off the ball, and lift the arms out wide. Inhale to slowly lower your torso back to the starting position. Keeping your movements slow allows you to work your abs.
This counts as one rep. Complete one set of 12 to 15 reps.