This is a true multi-functional exercise. It not only works the rear delts, but it fully taxes the entire posterior chain from head to toe, in addition to fixing your bent-over lateral raise mechanics.
It's a bent over lateral raise, but you perform it on a glute ham raise (GHR) station. This targets the glutes, hamstrings, spinal stabilizers, and postural muscles. Here's one of my NFL athletes showing how it's done as we bulletproof his shoulders and posterior chain for the demands of the season.
GHR Bent Over Lateral Raise
The torso position ends up being perfectly parallel to the floor so it's impossible to cheat. Your rear delts will get absolutely scorched.
Most lifters end up using excessive body english and an overly upright torso position when performing bent over lateral raises. They use their traps, upper back, and side deltoids more than the posterior portion of the shoulders, negating the desired effects. Doing these on a glute ham raise station eliminates these issues.
Although you'll have to decrease the weight compared to what you'd typically handle on bent over lateral raises, the stimulation to the targeted muscles will be well worth it.
But I Don't Have a GHR!
No glute ham raise, no problem. These can also be performed on a back extension machine.
Bent Over Lateral Raise, Back Extension Machine
Because the back extension station won't lock you in quite as strictly as the GHR, you can do them in a single-leg fashion to make them more challenging. This requires even stricter and more rigid body mechanics.
Be prepared for your glutes and hamstrings to be thrashed while you simultaneously build your posterior delts.