Rear Delt Fly: Dumbbell and Cable Versions for Balanced Shoulders

The rear delt fly trains the back of the shoulder by moving your arms out and back in a wide arc, with the elbows slightly bent and the shoulder blades staying mostly still. It is done light, slowly and for moderate to high reps. The dumbbell version, done bent over or chest-supported, is simple and needs almost no setup. The cable version keeps tension on the muscle through the whole range and is often easier to feel. Both are worth knowing. Most people go too heavy, squeeze their shoulder blades together and end up training their upper back and traps instead of the rear delts.

Why the rear delts are worth training directly

The deltoid has three parts: front, side and rear. Pressing work (bench press, overhead press, push-ups) hits the front delts hard. Rows and pulldowns involve the rear delts, but usually as a helper to bigger back muscles. The result, for many people who train, is shoulders that look and feel front-heavy.

Direct rear delt work helps balance that. It also gives the shoulder a fuller look from the side and the back. I would not claim it fixes posture on its own; posture is more complicated than one muscle, as our piece on whether perfect posture exists explains. But strong, well-used rear delts are part of a shoulder that copes well with a lot of pressing and a lot of desk time.

Dumbbell rear delt fly: how to do it

Bent-over version

1. Hold a light dumbbell in each hand. Stand with feet hip width, soft knees.
2. Hinge forward at the hips until your torso is roughly 45 degrees to the floor or a bit lower. Keep your back flat.
3. Let the dumbbells hang under your shoulders, palms facing each other, elbows slightly bent.
4. Lift the weights out to the sides in a wide arc, leading with the backs of your hands or your little fingers. Stop when your arms are roughly in line with your body.
5. Lower slowly over two to three seconds.

The bent-over version is efficient, but your lower back has to hold the hinge for the whole set. If that becomes the limiting factor, switch to the supported version.

Chest-supported version

Lie face down on an incline bench or rest your forehead on a padded surface, so your torso is supported. The movement is the same. Because you cannot use your legs or hips to cheat, it is often the cleanest way to feel the rear delts working.

Seated version

Sit on the end of a bench, lean your chest towards your thighs and perform the fly from there. It takes the lower back out of the equation and suits anyone who finds hinging uncomfortable.

Cable rear delt fly: how to do it

The cable version is my usual choice in sessions, because the cable keeps the muscle under tension even at the start of the movement, where dumbbells provide almost none.

1. Set both pulleys at about shoulder height on a cable station. No handles needed: many people simply hold the cable ends or the ball stops.
2. Take the left cable in your right hand and the right cable in your left, so the cables cross in front of you.
3. Step back until there is tension, arms straight out in front at shoulder height, elbows soft.
4. Open your arms out to the sides in a wide arc until they are in line with your shoulders.
5. Return slowly, letting the cables cross back in front.

A single-arm version, standing side-on to one pulley, lets you focus on one side at a time and often feels stronger. Our guide to cable attachments explains when a handle or rope helps and when nothing is better.

The faults that move the work elsewhere

Fault	What happens	Fix
Squeezing the shoulder blades hard	Mid-back and traps take over	Keep the shoulder blades roughly still; think “arms move, back stays”
Going too heavy	Swinging, shrugging, short range	Halve the weight; most people need very light dumbbells
Bending the elbows more as you lift	Turns into a row	Fix the elbow angle at the start and keep it
Arms travelling towards the hips	Lats and triceps join in	Move in a line out from the shoulders, not back towards the waist
Shrugging up to the ears	Upper traps take load	Long neck, shoulders down before each rep

The single most useful cue I give: imagine reaching your hands out to the walls on either side of you, rather than pulling them behind you.

Weight, sets and reps

The rear delts are small, and the fly uses a long lever. Weights that feel embarrassingly light are normal. Many fit adults use dumbbells somewhere in the 2 to 6kg range for clean reps, and there is no shame in starting lower.

• Sets and reps: 2 to 4 sets of 12 to 20.
• Tempo: controlled up, two to three seconds down. A short pause at the top helps.
• Effort: finish each set with one or two good reps left in reserve.
• Frequency: two or three times a week is fine, as the muscle recovers quickly at these loads.

Rear delt flies sit well at the end of an upper-body session, or paired with a pressing movement so you alternate front and back. They also make a sensible warm-up set before bench pressing.

Rear delt fly vs face pull vs reverse pec deck

The face pull trains the rear delts along with the external rotators of the shoulder and the mid-back. It is more of a combined shoulder-health movement. Our post on face pulls covers it properly.

The reverse pec deck is a machine version of the fly, with a fixed path. It is easy to load and very stable. The studio does not have one, but the cable fly does the same job with more freedom.

The rear delt fly itself isolates the back of the shoulder most directly. If you only do one, do this, and do it lightly.

When to take care

The fly is low-risk, but it still loads the shoulder through a long range. If you have a current shoulder injury, a history of dislocation, recent surgery or pain that comes on with arm movements, check with your GP or a physiotherapist first. The NHS guidance on shoulder pain is a useful starting point if something is already niggling. Stop if a movement causes sharp pain rather than muscular effort.

How we use it in 1-1 sessions

In the studio, the rear delt fly usually appears as a paired movement: a set of dumbbell or cable presses, then a set of flies, then back to the press. It keeps the session moving and gives the shoulder balanced work in the same block of time. With a 2-stack cable station and a full dumbbell rack, we can switch between the dumbbell and cable versions in seconds to find the one you feel best. If you want help building shoulder work around a desk-heavy week, see how 1-1 personal training in Highgate is set up. Plans start at £260 a month for four in-person sessions; full prices are on the training page.

Questions we get asked

Why can’t I feel my rear delts?

Usually the weight is too heavy or the shoulder blades are squeezing together. Drop the load, slow down, and lead with the backs of your hands. The cable version often helps people feel it for the first time.

Palms down or palms facing in?

Both work. Palms facing each other is often more comfortable for the shoulder; palms down can increase the rear delt focus for some people. Use what lets you move cleanly.

Can I do rear delt flies every day?

You could do a light set most days without much trouble, but two or three proper sessions a week is enough for progress and easier to sustain.

Are rear delt flies good for rounded shoulders?

They are a useful part of a broader approach that includes rows, mobility work and simply moving more during the day. On their own, they will not change how you sit.

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