Shoulder Rotation: Short 4/4, Training shoulder ER short is usually seen with resistance bands. It’s not a bad option if you can irradiate enough tension and maintain stability to truly exhaust the back of our shoulder, most people really don’t. Prone end-range isometric holds are my preference for this, they provide stability and allow for enough time under tension to undeniably feel posterior shoulder stuff working; go until failure, however long that takes, just ensure minimal tension is leak