Stand with your feet hip-width apart with a slight bend in your knees. Keeping your spine in neutral, lift a five- to eight-pound medicine ball overhead.
Begin to circle the ball to the left, in the largest circles you can make, while maintaining a still and stable torso.
Circle eight times, then reverse directions for another eight reps to complete one set. Aim for three sets.
As you stabilize your core while circling the medicine ball above your head, your abs will feel the burn. Your arms will feel it, too!