With a partner, straddle and sit on bench back to back with space between. Place feet flat on floor. First partner holds medicine ball with both hands.
Both individuals rotate torso through waist to same side. First partner hands medicine ball to second partner who retrieves ball. Both individuals turn to the opposite side to again exchange medicine ball. Continue to rotate ball to one direction. When finished, repeat opposite direction.
Start slow, gradually increasing speed throughout set. Perform prescribed repetitions or time. See Spot Reduction Myth