Target Body Part:
Starting Position: Kneel on a mat holding resistance cable or band handles in each hand with your arms straight in front of your body, at or just above shoulder height. Your elbows will remain straight throughout the exercise. Grip the handles with the thumbs wrapped around the handles and palms facing each other. Brace your abdominal / core muscles to stabilize your spine. Pull your shoulder blades down and back. Do not allow your low back to arch. Maintain these engagements throughout the exercise.
Downward Movement: Exhale. Slowly pull your arms in a wide arc back and down to the level of your hips. As you move through the arc, slowly rotate your arms so that your palms face upward. Keep your torso erect and do not allow your low back to arch.
Upward Movement: Inhale and slowly return your arms back to the start position keeping your elbows straight and torso vertical.
Try performing this exercise alongside a mirror to monitor any change in your back or shoulder position.
SOURCE: AMERICAN COUNCIL ON EXERCISE