training with dumbbells

The Dumbbell Rear Delt Fly

The dumbbell rear delt fly is one of the most challenging exercises to get right, partly because there is so much conflicting information. Besides, I see many people allow their larger muscles to direct the load away from the rear delts when performing flies.

To hopefully help you get the most out of rear delt flies, I’ll be talking about their benefits, how to perform them right, and what kind of alternatives you have.

What Are The Muscles Worked By The Dumbbell Rear Delt Fly?

The dumbbell fly is an isolation exercise that works your rear delts. Rear delts are arguably the most problematic muscles to isolate, and the rear delt fly is one of the few exercises that allow you to do so effectively.

Aside from your rear delts, the dumbbell rear delt fly also works upper back muscles like the traps or the rhomboids. However, you don’t want too much of the load to be eaten away by these larger muscles. Maintain proper form to make sure that you primarily load your rear delts.

Dumbbell Rear Delt Fly Benefits

You likely have got plenty of exercises incorporated into your training routine already, so why add another one? Well, here are three significant benefits of rear delt flyes.

Rear delt isolation

Rear delts are extremely difficult to target, and the dumbbell rear delt fly is one of the very few exercises that you can perform to strengthen this muscle. It’s arguably not the best, but because rear delt flies can be done anywhere if you have dumbbells, they are great for many people.

Better back definition

You may have a super-wide back, but if you haven’t paid attention to your small muscles, your back will look underdeveloped. Width without definition can look quite ugly, in my opinion.

Many other athletes and I think that aside from lats, you need to have developed traps and rear delts to get that ultra-defined look. Well-developed traps and rear delts add form and detail to your back, and they also wonderfully accentuate your back width.

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Neck and shoulder pain management

And the third benefit is that rear delt flies can help with neck and shoulder pain.

One study investigated the effect of strength training on shoulder and neck pain in office workers. During the 20-week intervention, training groups performed five dumbbell exercises:

  • Front raises.
  • Lateral raises.
  • Reverse flies (rear delt flies).
  • Shrugs.
  • Wrist extension.

By the end of the intervention, shoulder and neck pain significantly decreased in the training groups.

With that, reverse flies could be the cure to your shoulder and neck pain when combined with other exercises. It could be effective alone, but you shouldn’t focus your entire efforts on rear delt flies.

How To Do The Dumbbell Rear Delt Fly?

Here’s how to perform dumbbell rear delt flies correctly:

  1. Grab a pair of dumbbells.
  2. Stand with your feet shoulder-width apart.
  3. Hinge at your waist and bring your chest forward and down. Ideally, you would want your chest to be parallel to the floor, but not everybody has the flexibility for that. You may also bend your knees slightly to maintain a neutral spine.
  4. Allow the dumbbells to hang straight down and maintain a neutral grip.
  5. Inhale.
  6. Maintaining tightness in your core and keeping your back neutral, raise your arms out and to the side. Exhale as you lift the weight. Squeeze the shoulder blades together at the top, but don’t hunch your shoulders up.
  7. Keep your elbows slightly bent as you perform the movement.
  8. Lower the weight to the start position. Inhale as you do so.
  9. Repeat.

For starters, 8 to 12 reps and 3-4 sets should be enough.

Proper Form To Perform A Dumbbell Rear Delt Fly – Mistakes To Avoid

If you asked me which exercise people perform wrong the most, rear delt flies would perhaps be my #1 pick. Although rear delt flies are very simple, there are many, many things that you may do incorrectly.

To hopefully help you get the most out of this undeniably wonderful exercise, let’s now talk about the most common mistakes I see people make with the dumbbell rear delt fly.

Bringing the dumbbells backward

The dumbbells should only move in the lateral plane – that is, from side to side and out. You should NOT move the dumbbells back toward your butt when lifting the weight. If you do this, you will be engaging your back muscles much more than you would want.

Lifting heavy

Too often, I see people try to tackle heavyweight in rear delt flies. Excessive weight leads to two mistakes in this exercise:

  • Partial reps.
  • Bending the arms too much.

If you lift the dumbbells only half the way, you are going to get half the results. As for arm bending, this would turn the movement into a dumbbell row of sorts.

If you cannot do rear delt flies properly, drop the weight and work on the basics.

Swinging the weight

You should not assist yourself with your legs and back when lifting the dumbbells. Rather than use your larger muscles to satisfy your ego, you should drop your weight and work hard on performing clean reps. If you want to use your legs and back, do the deadlift.

Rounding the back

Don’t round your back – it’s a recipe for disaster. Although you probably won’t be using dumbbells heavy enough to injure your back, you should maintain a perfectly neutral spine throughout the entire range of motion. Your neck should be in line with the rest of your spine too.

A neutral back is a must in most strength exercises, and you don’t want to build bad habits and start rounding your back during critical lifts such as the squat or deadlift.

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What Are The Dumbbell Rear Delt Fly Variations And Alternatives?

Not everybody likes classical rear delt flies. If this applies to you as well, then give a shot to the following rear delt fly variations and alternatives.

One-arm rear delt fly

If you struggle with proper form, you may give the one-arm dumbbell rear delt fly a shot. The greatest thing about the one-arm rear delt fly is that you may use your free hand to hold onto something for additional support. With that in mind, this variation may help you better focus on your rear delt’s contraction.

Bench dumbbell rear delt fly

If you don’t feel comfortable with the traditional rear delt fly, try lying down on a flat bench

And actually, if you want to isolate your rear delts better, I’d recommend that you focus on the bench delt fly. However, if you are training at home, you may not have a comfortable bench lying around.

To perform this exercise, set your bench to a comfortable incline, lie with your stomach down, and complete the flies as described earlier. You may do this exercise on a flat bench too, but I find that an incline one is way more comfortable.

Seated dumbbell rear delt fly

You may also perform rear delt flies while seated

The setup in seated rear delt flies is slightly different from what you’d do when standing:

  1. Place your dumbbells near the edge of a bench.
  2. Sit down on the edge of the bench so that you can keep your knees close together.
  3. Hinge forward until your torso is nearly parallel to the ground.
  4. Reach down for the dumbbells.
  5. Start lifting.

Here’s a video to better demonstrate this variation:

Bent over cable rear delt fly

If you have access to a cable machine, you may replace dumbbell flies with cable flies.

What’s really nice about cable rear delt flies is that the cable machine will put a constant load on your delts. With a cable machine, the load goes along the cables, whereas with dumbbells, it is directed downward due to gravity.

Other than the change in equipment, bent over cable rear delt flies are the same as dumbbell flies. You may also use a band to emulate a cable machine.

Rear deltoid machine fly

Finally, if you have access to a rear delt machine, you may do rear delt flies with it as well. This is perhaps the easiest way to do flies because the machine guides the movement, so you’re less likely to make mistakes when performing the fly.

The Conclusion

The dumbbell rear delt fly is an excellent exercise if you do it right.

The most important tip to remember is NOT to lift heavy. Restrain your ego and start light. Besides, try only to move your shoulder joint to isolate the muscle better.

Jessica Carter
Jessica Carter
Jessica is an AFLCA certified personal trainer and holds a Masters degree in physical therapy from the University of British Columbia. She has been working in the field for 5 years and writes as a freelance about all things fitness related.