Resisted shoulder external rotations in neutral (Shoulder external rotation strengthening, with band, arm at side, standing; 01)

Stand in an upright position.
Hold a tensioned exercise band in both hands and bend your elbows to a right angle.
Keep your shoulder blades back and down and rotate your symptomatic arm outwards, keeping your elbow loosely by your side and your shoulder blades in a good position.
Control the movement then return back to the start position.
Relax and repeat.