Dumbell Lying One-Arm Rear Lateral Raise

The dumbbell lying one-arm rear lateral raise isolates the posterior deltoid by anchoring the torso against an incline bench, which removes the ability to cheat the weight up with body momentum. Working one arm at a time also lets you correct left-right strength imbalances that are common in the rear delts. Because the chest is supported, this variation places far less stress on the lower back than standing or bent-over rear delt raises, making it a good option for lifters who need to isolate the shoulder without loading the spine.

Muscles Targeted

• Primary: Posterior deltoid (rear delt)
• Secondary: Rhomboids, middle trapezius
• Tertiary: Infraspinatus and teres minor (rotator cuff), forearm stabilizers

Starting Position

Set an adjustable bench to roughly a 30-45 degree incline and lie face down with your chest and stomach pressed against the pad, one foot on each side of the bench on the floor for balance. Hold a single dumbbell in the working hand and let the arm hang straight down toward the floor with a slight bend in the elbow. Brace your free hand against the bench frame or the floor for stability, and let your head rest naturally so your neck stays in a neutral position.

Execution Steps

1. Set your shoulder blade by drawing it slightly down and back before initiating any arm movement
2. Lift the dumbbell out to the side in a wide arc, leading with your elbow rather than your hand
3. Raise until your arm is roughly parallel to the floor, keeping the slight elbow bend constant throughout
4. Squeeze the rear delt for a one-second pause at the top of the movement
5. Lower the dumbbell back down under control, resisting gravity rather than letting the arm drop
6. Complete all reps on one side before switching the dumbbell to the opposite arm

Form Cues

• Keep the torso pinned to the bench: Any lift of the chest off the pad turns the movement into a row and takes tension off the rear delt
• Lead with the elbow, not the hand: This keeps the emphasis on the shoulder instead of the upper back
• Maintain a fixed elbow angle: Bending or straightening the arm during the lift shifts work to the biceps and triceps
• Avoid shrugging: Keep the trapezius relaxed so the rear delt does the majority of the work
• Move slowly on the way down: The lowering phase is where most of the muscle stimulus occurs

Common Mistakes

• Lifting the chest off the bench: This turns the exercise into a rowing motion and reduces isolation of the rear delt. Keep your torso flat against the pad throughout.
• Using too much weight: Excess load forces momentum and shortens the range of motion. Pick a weight light enough to move with a slow, controlled arc.
• Raising the arm too high: Lifting past shoulder height shifts stress onto the trapezius. Stop once the arm is roughly parallel to the floor.
• Letting the dumbbell drop on the way down: This skips the eccentric portion of the lift, where much of the growth stimulus happens. Lower with the same control used to raise it.
• Rounding the neck forward: Craning the neck to watch the dumbbell adds strain to the cervical spine. Keep your head in a neutral, relaxed position.

Variations

• Bent-over one-arm rear lateral raise: Standing version that adds core and lower-back stabilization demands
• Two-arm incline bench rear delt raise: Trains both sides simultaneously for time efficiency once form is consistent
• Cable rear delt fly: Provides constant tension across the full range instead of the peak tension of a dumbbell
• Reverse pec deck fly: Machine-guided alternative that removes balance demands entirely
• Face pull: Rope-based variation that combines rear delt work with external rotation of the shoulder

Tips for Progression

• Add weight in small increments (2.5-5 pounds) only once you can complete all reps with strict form
• Increase time under tension by adding a two-second pause at the top of each rep
• Progress rep range from 12-15 reps toward heavier loads for 8-10 reps as strength improves
• Superset with the non-working arm to keep density high without extending rest time

Training Notes

Program the dumbbell lying one-arm rear lateral raise 1-2 times per week, typically toward the end of a shoulder or back session since it is a light, isolation-focused finisher. Work in the 10-15 rep range per arm for 2-3 sets, resting 45-60 seconds between sets. Because rear delts respond well to frequent, moderate-volume work, this exercise pairs well with pressing-dominant shoulder days to balance anterior and posterior shoulder development.