Rear Delts Training for the Slim Woman: 135 to 160 lbs, Recomp Phase

For a woman at 135 to 160 pounds in a recomp, I train rear delts with face pulls, bent-over rear delt flies and band pull-aparts. Do it on upper body days of a four-day upper/lower split, add weight when every set reaches the top of the rep range, and expect visible change in about 8 to 12 weeks.

Slim is my name for women between 135 and 160 pounds, usually a pear, hourglass or inverted triangle shape, in a recomp phase: losing fat and building muscle at the same time on 1,700 to 2,000 calories and 120 to 145 grams of protein a day.

If you are a woman at 135 to 160 pounds whose shoulders round forward, in photos, in mirrors, in your natural resting posture, the posterior deltoid is the muscle most directly responsible for fixing that, and it is almost certainly undertrained relative to everything else you are doing.

The rear delt is the most undertrained shoulder muscle in women’s fitness programs without exception, it receives zero stimulus from pressing movements, is never covered by mainstream workout plans, and its underdevelopment is directly responsible for the rounded, caved-in shoulder appearance that no amount of front delt or chest work will correct.

What muscles are you training in your rear delts?

The posterior deltoid is the back portion of the three-part deltoid muscle. It originates along the spine of your shoulder blade (the bony ridge across the back of your scapula) and inserts at your upper arm alongside the other deltoid heads. Its function is to pull your arm back, shoulder extension, and externally rotate your shoulder (rotating your upper arm outward).

Its development creates the three-dimensional shoulder appearance visible from the side: the full, rounded cap of a developed shoulder requires all three heads, and the rear portion is the one that most women completely lack. Without rear delt development, your shoulder profile appears flat from the side and your arm hangs in internal rotation, contributing to the rounded-forward appearance.

How does body shape change rear delts training?

Pear Shape

Upper body development is your structural priority. Rear delt training should be high volume, 4 sets twice per week, to develop the three-dimensional shoulder appearance that widens and develops your upper body.

Hourglass Shape

Rear delt development enhances your natural balance. Three-four sets twice per week.

Inverted Triangle Shape

Your shoulders are already wide. The goal is depth and three-dimensionality, not width. Rear delt development creates the back-of-shoulder fullness visible from the side. Moderate volume, three sets twice per week.

What is the exact rear delts workout for Slim?

Exercise 1: Face Pull

Set a cable rope at face height. Grip both rope ends with palms facing down. Step back for tension. Pull the rope toward your face while simultaneously pulling the rope ends apart, elbows flare out and upward. Finish with elbows at or above shoulder height, hands beside your head. Hold for 1 second. Return slowly.

Sets: 4. Reps: 15. Rest: 60 seconds. Starting weight: 20 pounds. Progressive overload: add 5 pounds monthly, this is a small muscle trained for endurance as much as strength. Common mistake: elbows dropping below shoulder height, removing rear delt emphasis.

Exercise 2: Dumbbell Rear Delt Fly (Bent Over)

Sit at the end of a bench or stand bent forward at your waist until your torso is near parallel to the floor. Let both arms hang straight down, a light dumbbell in each hand. With a slight bend in your elbows, raise both dumbbells out to the sides, the movement is horizontal abduction, arms moving away from your body while parallel to the floor. Do not raise above shoulder height. Lower slowly.

Sets: 3. Reps: 15. Rest: 60 seconds. Starting weight: 8 to 10 pounds per hand. Progressive overload: add 2 pounds when all reps are completed with no torso rocking. Common mistake: raising the dumbbells too high or using body momentum, keep your torso fixed, movement only at the shoulder joint.

Exercise 3: Band Pull-Apart

Hold a resistance band with both hands in front of you, arms straight, at shoulder height. Pull the band apart by moving both hands simultaneously outward and backward until the band touches your chest. Hold for 1 second. Return slowly. This exercise trains your rear delts, rhomboids, and external rotators simultaneously and can be done anywhere.

Sets: 3. Reps: 20. Rest: 45 seconds. Starting resistance: light band. Common mistake: allowing your elbows to bend, keep arms nearly straight throughout.

What should you expect at week 1, week 4 and week 12?

Week 2: Shoulder posture begins naturally correcting, the externally rotated position becomes easier to maintain.

Week 8: Three-dimensional shoulder appearance visible from the side.

Week 12: Natural resting shoulder position is neutral rather than internally rotated.

What should you read next?

Pair this with Slim shoulders training and Slim traps training, and see the high protein diet for Slim. To work with me, start with the XPL quiz, which is my intake form for every client and confirms whether Slim is your category, then see coaching options and pricing.

Written by Zavier King, personal trainer in Houston and online coach at XPL. ISSA Certified Personal Trainer and NASM Nutrition Coach.