It's such an isolation movement I prefer to use a machine...reverse pec flies seem to hit the rear delts very well. You can also get the mid traps a little too depending on how you do them.
The very first move I do for my rear delts is a hammer strength reverse row machine, its plate load. I do a warmup then do a big drop set, that way when I do the heavy seated reverse rows I isolate my rear delts even more. My rear delts are pretty developed...
Sit sideways on reverse fly machine, your rear delt will be fully stretched. Keep shoulder low to keep your back out of it. 5 sets of 15-20 reps then onto back workout.
single arm bent over reverse fly. you have far more range of motion with one hell of a contraction. high rep (20-30). john meadows suggested these to me.
I only do a couple sets of seated bent over rear delt raises. One heavy and one light usually occasionally ill hit 3 sets.. but as others have said they get hammered in pretty much every single back exercise
I like to take any normal rear delt movement and superset it with bent over cable.grab the left cable in your right hand and vise versa.bend over at the waist lock your elbow in a bent position and keep it there don't let it straighten out!now short movement pull to contract the rear delt these are awesome.
nt for me, i do at least 2 isolations for rears and mine r still not very developed at all. but round shoulders is hard for me maybe cuz im 6'4'' and dont have real broad shoulders....sux...but if phil heath can do it....
bent rear raises with a cable. you can stretch yr arm across body with tension, bring it back with arm as straight as possible. that works for me. constant tension, nice full range.
My fav is sitting on a cable row station. Hook up a rope. Pull it like a row, but keep it high around the chin/mouth area. That gets my rear delts more sore than any kind of reverse fly movement.
Doing it on a seated cable row allows me to go heavy. If I try to do it standing like on a cable tower, I have to struggle to not get pulled myself and lose balance.