Shoulder Rhythmic Stabilization
A challenging exercise that focuses on shoulder and scapular stabilization. It works all of the muscles of the shoulder girdle and can be very fatiguing.
You can perform this exercise on a ball or on the floor with your knees bent. You will start with a light weight in your extended arm. Perform small circles in one direction for 30 seconds, then circles in the other direction for 30 seconds. Next, protract your arm (reaching up so your shoulder blade is off the floor/ball) and perform little circles in 30 second-bouts clockwise and counterclockwise.
You want to make sure the motion is slow and controlled.