The cable crossover rear delt fly isolates the posterior deltoids by having the lifter stand between two high cable pulleys, cross the handles in front of the body, and pull them apart and back in a reverse-fly arc. Constant cable tension keeps the rear delts under load throughout the entire range of motion, which is harder to achieve with dumbbells. This exercise is commonly used to correct the rounded-shoulder posture that comes from underdeveloped rear delts relative to the front and side heads.
Muscles Targeted
- Primary: Posterior (rear) deltoids
- Secondary: Rhomboids, middle trapezius
- Tertiary: Rotator cuff muscles (infraspinatus, teres minor) as stabilizers
Starting Position
Set both pulleys on a cable crossover station to roughly shoulder height and attach a D-handle to each. Grasp the left handle with your right hand and the right handle with your left hand, crossing your arms in front of you, then step back to create tension. Stand with feet shoulder-width apart, knees slightly bent, chest lifted, and a slight forward hinge at the hips.
Execution Steps
- Brace your core and pull both handles out and back simultaneously in a wide arcing motion
- Keep a slight bend in the elbows throughout, avoiding a straight-arm lockout
- Drive your hands back until they are roughly in line with your shoulders, squeezing your shoulder blades together
- Pause briefly at full contraction to maximize rear delt engagement
- Return the handles to the crossed starting position under control, resisting the cable pull
- Repeat for the desired number of reps
Form Cues
- Lead with the elbows: Think of pulling your elbows back and out rather than just moving your hands
- Keep the torso still: Avoid using back swing or hip drive to move the handles
- Squeeze the shoulder blades together at the top to fully engage the rear delts and upper back
- Maintain a slight forward lean from the hips, not the lower back, to keep tension on the target muscles
- Control the return phase instead of letting the cables snap your arms forward
Common Mistakes
- Using too much weight: Excess load turns the movement into a shrug or row, shifting work to the traps; use lighter weight and prioritize form.
- Straightening the elbows completely: This shifts strain onto the elbow joint and reduces rear delt tension; keep a soft bend throughout.
- Rounding the upper back at the start: This slackens the rear delts before the pull even begins; keep the chest lifted.
- Rushing the reps: Fast, jerky reps rely on momentum rather than muscle contraction; slow the tempo down.
- Pulling the hands too high or too low relative to the shoulders: This shifts emphasis to the traps or lats instead of the rear delts; keep the arc at shoulder height.
Variations
- Bent-over dumbbell rear delt fly: Free-weight version that removes the constant cable tension but adds stabilization demand
- Machine reverse fly: Fixed-path version offering maximum stability for beginners
- Single-arm cable rear delt fly: Unilateral variation that helps correct side-to-side imbalances
- Face pull with rope attachment: Similar posterior deltoid emphasis with more upper trap and rotator cuff involvement
- Seated cable rear delt fly: Seated position removes lower body movement, isolating the upper body further
Tips for Progression
- Add weight in small increments only once shoulder blade squeeze is consistent on every rep
- Increase time under tension by adding a 2-second pause at the point of full contraction
- Progress from a bilateral to a single-arm version to increase stability demand
- Add a second set or a few extra reps before increasing load, since rear delts respond well to higher volume
Training Notes
Program the cable crossover rear delt fly 1-2 times per week as an accessory movement for shoulder or back day, typically toward the end of the session. Use light weight for 12-15 reps across 3 sets, resting 45-60 seconds between sets, since the rear delts are a smaller muscle group that responds well to higher rep ranges and shorter rest periods.