Prone scapula retraction with UL "T" in ER (Scapular retraction stabilization, prone-T, lifting arms, palms forward)

Lie on your front with your forehead rested on a small towel.
Keeping them straight, move your arms out to your sides.
Rotate your forearms out so that your palms face forwards.
Keeping your chest and head in contact with the floor throughout, squeeze your shoulder blades together, and then lift your arms off the floor.
Hold this position.
Relax and repeat.