Sit in front of the cable machine and grasp the long bar with a pronated (overhand) elbow-width grip.
Slide your buttocks backward and lean back so that your torso is upright, your back is straight, and your arms and shoulders are extended in front of you.
Execution
Exhale as you pull the bar toward your upper chest, keeping your elbows at shoulder height and your body still.
Hold for a count of two.
Inhale as you slowly return the bar to the starting position, with your shoulders and arms extended in front of you.
Repeat.
Comments and tips
Keep your elbows at shoulder height. If your elbows drop, your latissimus dorsi will get involved and the cable rear delt row will become more of a standard wide-grip cable row. Another circumstance in which your latissimus dorsi will get more involved is if you keep your torso leaning forward.
“Elbow width” means the width of your elbows when raised out to the sides to shoulder height.
Since you are targeting your posterior deltoid with the cable rear delt row and not your relatively larger latissimus dorsi, use a lighter weight than you would for the wide-grip cable row.