Prone scapula retraction with UL "M" (Scapular retraction stabilization, prone-M, lifting arms, palms down)

Lie on your front with your forehead rested on a small towel.
Keeping them straight, move your arms out from your sides a little.
Your palms should face the floor.
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.