Starting Position: Lie supine (on your back) on an exercise mat or firm surface, bending your knees until your feet are positioned flat on the floor 12-18" from your buttocks. Place your arms at your sides, with elbows fully extended and palms facing inward. Breathe deeply for a 30 seconds relaxing your body and allowing gravity to gently pull your lower back and shoulders towards the floor.
Depress and retract your scapulae (pull your shoulder down and back) without increasing the arch in your low back or lifting your hips off the floor. Contract your abdominal / core muscles to flatten your low back into the mat and hold this position throughout the exercise.
Shoulder Flexion: Exhale and gently lift and rotate your arms overhead, continuing to rotate them towards the floor without arching your lower back, bending your elbows or changing your wrist position. Your goal is to lift and rotate your arms overhead and backwards to 150+ degrees (starting point = 0 degrees; complete rotation where the thumbs touch the floor overhead = 180 degrees). Hold this position for 15-30 seconds before slowly returning to your starting position.
In this overhead position, attempt to: (1) fully extend the elbows without arching your low back or shrugging your shoulders and (2) keep your shoulders depressed (avoid any upward shrugging).
Shoulder Extension: Inhale and slowly return your arms back to your starting position.