How to Work Your Rear Delts Correctly

Are you struggling to find a good rear delt workout?

If so, you’re not alone. The rear delt, or posterior deltoid, is the most commonly neglected of the three sets of fibers that make up the shoulder muscle (anterior, middle and posterior). A lot of people don’t work this part of the shoulder (most traditional shoulder exercises are anterior dominant), or if they do, they don’t do it quite right.

We’re going to help correct that, by pointing out the key mistakes people make when working out the rear delts, and show you how to work this part of the shoulder correctly.

Common Rear Delt Mistakes

If you want to build all-round size in the shoulders, and not exclude the rear delts, you’ll need to do an exercise that isolates the rear delts. That’s because the rear delt is surrounded by other muscles, such as the triceps, rhomboids and traps, which often take the load of a lift and prevent you from getting much growth in the rear delts.

The rear delt fly is the most common isolation exercise for this muscle. It’s a great way to target the rear delt, but there are some very common mistakes people make with it. These mistakes lessen the benefits for the rear delts, which is the reason for doing this exercise in the first place.

Here are the two most common mistakes with a rear delt fly.

Going Too Heavy

You need to go lighter in weight with the rear delt fly if you want to ensure that you actually target the right muscle.

People often go too heavy, with the same kind of weight they’ll use for a dumbbell row. The problem with going too heavy is that you’re forced to recruit the other muscle groups around the rear delts. These muscles - such as the triceps and back muscles - end up doing most of the work, and you don’t really work the rear delts at all.

Going Too Far Back

The other problem with the rear delt fly is pulling the weights back, instead of out.

People will bring the weight back towards their hip, in the fly motion. This is not necessarily a bad exercise - it’s safe, and it will give you a decent workout for the back muscles - but it’s not going to do much for the rear delts.

Like with the previous mistake, you end up working all the muscles around the rear delts instead. To properly target the rear delts, bring the weight up in line with your shoulders, straight  up instead of back towards the hip.

Why Rear Delts Are Important

Is it really that important to put so much focus on the rear delts?

If you just want to build mass, you don’t need to worry about the rear delts so much. Exercises like the rear delt fly aren’t mass-building exercises, and doing presses and rows with heavier weights are better at putting on more overall size.

But if you want to round out your physique, it’s important that this muscle doesn’t get neglected. Naturally, with compound lifts, the other muscles around the rear delts will grow faster, leading to an imbalance.

You’ll find training the rear delts can also help build better posture and mobility. Stronger rear delts help stop your shoulders from rounding forward, creating a healthier (and more attractive) posture. They also help to stabilize the shoulders, and provide better mobility and range of motion from this joint.

How to Work Rear Delts Properly

To work the rear delts properly, you need to isolate them. As mentioned already, if you don’t specifically target the rear delts, other muscles will end up doing all the work in your lifts.

To do that, go with lighter weights, and really focus on getting your form perfect. This is not the kind of exercise you want to just ape out and lift the heaviest weight you can.

You may want to do your rear delt fly one arm at a time, to get your focus 100% on the correct movement. The following video does a great job of showing how to do this, while correcting some of the mistakes we pointed out earlier.

You can also do it two arms at a time though, as shown in this video:

With both variations, the main thing to note is that you should lift the dumbbell out, not back. Keep your elbows in line with your shoulders the whole way through the lift.

You can also work out the rear delts with a cable machine, instead of with dumbbells. One option is to do a cable rear delt fly, standing up and holding the cable in one hand, performing the same motion, and keeping your arms level with the shoulder.

Another is the face pull. Using a rope attachment (like you might use for tricep pulldowns), set the level at face height, pulling the cable back towards your face. This will work the rear delts, as well as several upper back muscles.

When to Include Rear Delts in Your Workout

You don’t need to work out rear delts every day. Once a week is fine, as long as you don’t totally neglect this muscle.

When to work them out depends on your splits. If you split by muscle group, shoulder day is the natural time to work rear delts. If you do push/pull, add either rear delt flys or face pulls in on your pull day.

You could also train rear delts on back day, or after deadlifts. A great idea is to fatigue the surrounding muscles - triceps, back, etc - before you do rear delts, to force you to really activate them and avoid relying on these supporting muscles.

However you do it, start training rear delts today. By adding one more exercise - or fixing your form, if you already do rear delt flys - you can build better posture and more impressive all-round shoulders.