Best Isolation Techniques for Rear Delts

To isolate your rear delts, you need to stop moving your weight and start moving your upper arm. When you do movements like cable reverse flys, move your elbow back and outward and keep your shoulder blade mostly still to keep your traps and rhomboids from taking over. Before adding volume, start with something lighter to help your mind and muscles link. For consistent tension, cables and machines are usually better than dumbbells.

Why Your Rear Delts Never Seem to Activate​

One of the most annoying muscles to work is the rear delts. This is because nearby muscles that are bigger and stronger quickly take over when the movement gets sloppy, or the weight gets too heavy. Your traps, rhomboids, and lats can all take over rear delt movements before your posterior deltoid has a chance to make a real difference. Two things are usually to blame for poor muscle isolation: the wrong arm movement and too much weight. If you let your elbows hang, or your shoulder blades press hard together, you're moving the work to a different area of your body. Getting better at your workouts and learning how arm path affects recruiting the rear deltoid will make a big difference in how often you feel the muscle moving.

How to Actually Feel Your Rear Delts Working​

One simple change in thought will make your back delts really work: instead of thinking about moving the weight, think about moving your upper arm. That one change makes the connection between the mind and muscles stronger and makes isolating the rear delts much more effective.
Put the pulley at shoulder height on a cable rear delt fly, and instead of pulling with your hand, drive your arm back and outward. Do not move your shoulder blade too much. This will make the back delts work instead of your traps.
Before adding more volume to your workouts, start with lighter resistance to get used to how this feels. Progressive overload is a much better way to get your shoulder to get bigger once you can regularly feel the muscle working through the whole range.

The Best Rear Delt Isolation Exercises, Ranked​

Once you can regularly feel your rear delts working, you should choose exercises that make it easier to keep that connection. All movements do not equally work out the posterior deltoid, and some give you a lot more control over tension and range of motion than others.
How do the most common options measure up? There are different exercises for the rear delts; some just make it easy to feel the muscle work.

• Reverse pec deck: reduces the need for force and stability
• Cable reverse fly: the resistance stays the same throughout the whole range of motion
• Dumbbell backward fly: easy to do, but the top loses its tension
• Rear delt row: a good variation, but working the traps more becomes more important as you lift bigger weights.

For isolation, cables and machines usually work better than dumbbells because the resistance stays the same throughout the activity. Choose the option that lets you clearly feel your back delts working, and keep working on it.

Form Mistakes That Are Killing Your Rear Delt Gains​

Even small form mistakes can quietly move tension from your rear delts to your traps, rhomboids, or upper back. This means that no matter how hard you work, the muscle you're trying to train stays undertrained. Most of the time, people make the mistake of moving the scapula more than they move the upper arm through the shoulder joint. Your rhomboids and mid-traps do most of the work when you squeeze your shoulder blades together instead of pulling your elbows back. Using too much weight on the reverse pec deck makes this trend more likely. The position of the elbows is also important. Letting them drop changes the pull angle and makes it much harder to strengthen the back shoulder. Maintain a straight line between your upper arms and the floor, keep the pace steady, and resist the urge to add more weight than is necessary for clean execution.

How to Program Rear Delt Work Into Your Routine​

The rear delts do well with direct training two to three times a week. They also recover quickly enough to handle that frequency without much trouble because they're a small muscle group. You can work on your back delts alone after pressing or pulling, when they are already warmed up and ready to go. When your technique is good and you keep the same amount of tension throughout each rep, two to four sets per session is usually enough. Not only weight, but also performance quality and range of motion can help you see how far you've come. Don't add too much volume, because adding more sets won't make up for bad separation. Long-term results will be better if you keep back-delt work manageable and regular instead of doing random high-volume sessions that hurt your form and put stress on muscles around your shoulders.

 

[talktomybiceps]

I’ve always gotten more out of rear delts with lighter weight and really controlling the arm path, especially on reverse pec deck and cables. Once I stopped trying to turn every rear-delt set into a heavy row, they started feeling way more isolated.

 

[chris_miller]

I like the idea of focusing on moving the upper arm instead of just moving the weight because it makes it much easier to actually feel the rear delts doing the work.