Abs exercise: Roundhouse Kick

I love roundhouse kics for abs. Stand with a punching bag in front of you. Lift your leg as if stepping over a bench, and rotate your hips so the laces of your shoe, not the side of your foot, strike the bag. Lift and rotate the heel of your opposite foot. Flex your obliques on impact—then slowly pull your leg back. Do 25 kicks with each leg.