Stand straddling seat and facing away from ball ramp with hips and knees slightly bent. Hold medicine ball with both hands.
Rotate body to highest side of ball ramp. Place medicine ball on ramp. Release ball and turn to opposite side. Grasp ball as it travels to other side. Continue to transfer ball to highest side of ball ramp and catch it on opposite side. When finished, adjust ramp to opposite incline and repeat movement in opposite direction.
Start slow, gradually increasing ramp incline, speed, and range of motion. Using heavier ball will also increase difficulty of exercise. Perform prescribed repetitions or time. Since hips are slightly bent, some hip adduction / abduction occurs along with internal / external rotation. See Medicine Ball Standing Twist with partner. Also see Spot Reduction Myth.