Dumbbell Lying One-Arm Rear Lateral Raise
Also works: Middle Back
Chest down on a bench set to about 15 degrees, one dumbbell in one hand, you raise the arm out to the side until it is parallel to the floor. Working one side at a time on a low incline removes both the balancing act and the temptation to heave, which is why this is one of the cleanest ways to load the rear deltoid.
Own the movement
Set up first, then execute. Every cue below is something you can check on your next set.
Before the first rep
- Set the bench to roughly 15 degrees from the floor — low enough that your working arm hangs straight down.
- Lie chest-down with your forehead just past the top edge so your neck is neutral and you can breathe.
- Grip the bench leg or frame with the free hand and pull yourself lightly into the pad to stop the torso rolling.
- Let the working arm hang straight down, palm facing your torso, with a fixed 10-20 degree bend at the elbow.
- Start with a dumbbell in the 4-8 kg range. Almost everyone picks up twice what they can lift correctly here.
Every rep
Breathing & tempo — Exhale as the arm sweeps up, inhale on the way down. One second up, one second held at parallel, two to three seconds lowering.
Sets, reps & load
Where to start, and what to change when it stops being hard.
Start at 4-6 kg. Being able to control 10 kg for 15 strict reps per side with a one-second hold at the top is a solid intermediate marker. Add reps before weight here — go from 12 to 20 at the same dumbbell, then step up 2 kg and drop back to 12. If the top of the rep stops looking parallel, the dumbbell is too heavy.
What goes wrong
The errors that show up most often, and the cue that fixes each one.
Anchor the free hand on the bench leg and pull yourself into the pad. Have someone watch your shoulders stay square, or film one set from the head end — the rotation is obvious on video and invisible from inside.
Stop dead when the elbow hits shoulder height. Set a mental line at the horizon and let the trap stay relaxed; the last 20 degrees adds nothing but upper-trap work.
Fix the elbow at a slight bend and cue the movement as the hand travelling away from your body in an arc, not toward your hip. Drop 2 kg if the arm keeps folding.
Pause for a beat with the arm hanging dead before you start the next rep. Rear delt work is short-range; momentum steals most of what little tension there is.
Why bother
The rear delt gets cheated more than any other muscle because standing bent-over versions let you use your hips and lower back as a catapult. Lying face down on a bench takes the hips out of the equation completely — there is nothing left to swing with, so the 6 kg you can actually raise is the 6 kg the rear delt lifts.
Going one arm at a time buys two things. Your free hand grips the bench leg, so the torso cannot rotate to sneak the weight up, and you get an honest read on the side-to-side difference most people carry from years of one-handed work. If the left arm stalls three reps earlier than the right, that gap has been hiding inside your rowing all along.
Where it fits
After your rows and presses, at the end of a pull or shoulder day. Two to three sets per side, two or three times a week — the rear delt recovers quickly and responds to frequency. Pair it with face pulls rather than with more heavy rowing, which already loads it in a straighter line.
If this one isn't it
No kit, too hard, or too easy — here's where to go instead.
Same job, different kit
Start here instead
Asked and answered
Why one arm at a time instead of both?
Because the free hand holds you to the bench, so your torso cannot rotate to help. It also exposes side-to-side differences that the two-arm version hides — most people find one side gives out several reps earlier. The cost is double the time under the bench, which is the only reason to prefer the two-arm version.
How heavy should the dumbbell be?
Lighter than you think. The rear delt is a small muscle working at the end of a long lever arm, so 4-8 kg is a realistic starting point and 10-12 kg for strict reps is respectable. If you need to jerk the weight to reach parallel, you are training your lower back and traps instead.
I feel this in my traps, not my rear delt. What is wrong?
Two usual causes. You are raising the arm above shoulder height, which hands the job to the upper trap, or you are actively squeezing the shoulder blades together and turning it into a rhomboid exercise. Stop the arm at parallel and let the shoulder blade move only as much as it wants to.
Is the 15-degree incline important, or can I use a flat bench?
The slight incline lets the arm hang clear of the floor with a normal-height bench and keeps your face off the pad. A flat bench works if it is high enough that a 10 kg dumbbell can hang without touching down; if it is not, the range gets cut and the bottom of every rep disappears.