Lie supine on stability ball with feet on floor and knees bent. Hold medicine ball with both hands. Position ball above with arms nearly straight. Partner distances themselves facing legs of participant in position to receive and throw ball back to participant.
Lower ball back over head and throw medicine ball forward to partner by forcefully extending shoulder. Partner catches ball and throws ball back. Catch ball and repeat.
Partner can either perform same exercise opposite of participant or stand to catch and throw ball back to participant. Perform prescribed repetitions or for time. Although throw is powered by shoulder extension, dynamic Spinal Flexion may be seen in some individuals.