Instructions
Seat yourself comfortably on a solid chair, with your back straight and unsupported. Keep your feet planted about shoulder-width apart, with your arms hanging loosely by your sides.
Relax your shoulders so they hang as low as possible.
Slowly raise your shoulders upwards in a shrugging motion.
At the top position, allow your chest to expand by pulling your rear shoulder blades together, bringing your shoulders back.
Slowly relax and lower your shoulders back down to the starting position.