HOW: Start by holding onto a medball with both hands in a standing position with your knees slightly bent and hinged forward at the waist. From here, rotate the upper half of your body quickly to one side and the other while keeping the rest of your body still. Repeat for the prescribed amount of reps.
FEEL: .You should feel your core and mid back muscles working to rotate the upper half of your body from side to side.
COMPENSATION: Don’t move your lower body as you rotate the ball from side to side.