The shoulder joint is complex, and many people focus primarily on the front and middle heads of the deltoid muscle. When the back portion remains underdeveloped, this imbalance can lead to a forward-slumped posture and compromise overall shoulder health. Training the posterior deltoids is necessary for achieving a balanced, three-dimensional look and for stabilizing the joint during various movements. Learning to target this specific muscle group effectively is the first step toward building stronger, healthier shoulders.
Understanding the Posterior Deltoid
The posterior deltoid is one of the three heads that make up the deltoid muscle, capping the shoulder joint at the rear. This triangular muscle originates from the spine of the scapula and inserts onto the humerus. Its primary functions include shoulder extension (drawing the arm backward) and horizontal abduction (moving the arm away from the midline when parallel to the ground). It also assists in lateral rotation, helping to turn the arm outward.
Underdeveloped posterior deltoids create a muscular imbalance, allowing stronger chest and anterior deltoid muscles to pull the shoulders forward, contributing to poor posture. Many lifters mistakenly believe that general back exercises like rows sufficiently address the rear delts. However, larger muscles, such as the latissimus dorsi and trapezius, often dominate these movements. Targeted isolation work is necessary to provide the specific stimulus required for growth and stabilization, which reduces the risk of injury.
Key Exercises for Rear Shoulder Development
Effective rear deltoid development relies on isolation exercises that focus on the muscle’s primary function of horizontal abduction.
Dumbbell Bent-Over Reverse Fly
This highly effective movement is typically performed with light to moderate weights. To execute this, bend at the hips until the torso is near parallel to the floor, allowing the arms to hang down. The movement involves raising the dumbbells out to the sides in a wide arc, keeping a slight bend in the elbows, until the arms are parallel to the floor. Focus on squeezing the rear delts at the top before slowly returning to the start position.
Face Pull
The Face Pull uses a cable machine or resistance band and targets both the rear delts and the external rotators of the shoulder. Using a rope attachment, pull the rope toward the face, specifically aiming for the hands to finish near the ears. The path of motion involves pulling the elbows back and out. Focusing on the external rotation component helps maximize posterior deltoid activation.
Band Pull-Apart
The Band Pull-Apart is an accessible exercise that requires only a light resistance band and can be performed almost anywhere. Start with arms extended straight out at shoulder height. Pull the band apart horizontally across the chest until the arms are extended out to the sides. This movement is excellent for high-repetition sets and for establishing a strong mind-muscle connection with the back of the shoulders.
Cable Rear Delt Row
For increased resistance, the Cable Rear Delt Row can be performed using a cable pulley set to chest height and a double-handle attachment. Stand facing the machine and pull the handles toward the chest or abdomen, driving the elbows back and slightly out. This variation provides consistent tension throughout the range of motion, which is a benefit of cable exercises over free weights.
Isolating the Muscle Avoiding Technique Errors
The posterior deltoid is notoriously difficult to isolate, meaning proper technique is far more important than the amount of weight used. A common error is using excessive weight, which causes other, larger muscles like the traps and rhomboids to take over the movement. When performing a reverse fly or similar movement, the focus should be on a slow, controlled contraction and a complete range of motion.
A frequent mistake is allowing the upper trapezius muscle to shrug the shoulders toward the ears, which removes tension from the rear delts. To avoid this, the shoulders should be kept down and away from the neck throughout the entire set. Furthermore, it is important to minimize scapular retraction, which is the squeezing of the shoulder blades together, as this recruits the rhomboids instead of the rear delts.
For maximum isolation, the goal is to move the arm relative to the torso without significantly moving the shoulder blade itself. This requires focusing on driving the movement with the elbows, moving them out and back, while consciously trying to keep the shoulder blades relatively still. Using a lighter weight allows for a strong mind-muscle connection, ensuring the posterior deltoid is the primary muscle performing the work. The return phase of the movement, the eccentric portion, should be performed slowly over several seconds to increase time under tension.
Integrating Rear Deltoid Training Into Your Routine
For optimal development, the posterior deltoids respond well to higher training frequencies due to their composition of both fast-twitch and slow-twitch muscle fibers. Including isolation work for this muscle group two to three times per week is recommended to provide sufficient stimulus and recovery. Beginners can start with a total weekly volume of four to six dedicated sets, with more experienced individuals benefiting from a range of ten to sixteen sets per week.
The best repetition range for these exercises typically falls between 10 and 20 repetitions per set, utilizing moderate weight. This higher rep scheme helps to reinforce the necessary mind-muscle connection and prevent the use of momentum, which is crucial for isolation. These exercises can be strategically placed at the beginning of a workout (pre-exhaustion) or performed at the end of a session as a finisher.