isometric shoulder external rotation at 90° abduction, resisting rotation toward ceiling with opposite hand
Stand, elevate the arm to 90 degree by the side, bend the elbow such that hand facing forward, rotate the arm towards ceiling. Place other hand just above the wrist, further move the arm towards the ceiling against the resistance of other hand. Release the pull and repeat.
Nothing here is a prescription. Your physiotherapist decides which of these are yours, and when.
