Isometric GHjt ER(N) at 45 degrees in side lying with weight (Shoulder external rotation strengthening isometric, with dumbbell, arm at side, at 45°, side lying)

Lie on your side with your arm to be exercised uppermost.
Hold a weight in your other hand.
Ensure your head is comfortable.
You may wish to use a pillow.
With your upper arm resting down your side, bend your elbow to 90 degrees.
Rotate your forearm so that it turns up towards the ceiling a little, with your upper arm still in contact with your body.
Holding this position, pass the weight into your upper hand.
Do not allow your arm to move.
Keep your shoulder blades gently pulled back and hold this position.
Remove the weight before your lower your upper arm back down again.