It took me while before i was able to get something out of dumbell and cable laterals.
As a lot of people i used:
- the upper traps to generate too much momentum, giving the side delt a break
- torso swing
- slight external rotation of the shoulder so that part of the stress was transferred from the side delt to the stronger biceps-front delt chain.
It wasn't until I stumbled upon the lateral raise machine of technogym that i felt what it was like to target the side delts...
This machine has you seated with your arms FIXED next to your sides and the forearm bent at 90 degrees. Just using the upper traps or raising the shouldergirdle will NOT move the stack, only raises started from the side delt will do something and the traps become what they are supposed to be, an assiting muscle and not a primary mover....
Anyway I adopted the machine style and brought it to my gym where they unfortunately don't have this machine.
I grab some dumbells, with the forearm bent at even slightly more than 90 degrees (closer to the torso than floor that is) and the elbows just a bit behind the lower lats. I lean slightly forward, a bit like in bent rowing, only higher angle, just enough so to that the side delts are exposed maximally to gravity when your arms are raised. stick my head forward so that its not the upper traps that assist but rather the medial trap. From this point I do sets of 12 reps with a medium weight so that i can focus on good from.
Offcoarse it is also necessary to train with heavy weight but I use the 5 * 5 or 5 * 8 heavy overhead presses for that.
Any way I cannot use bent arms with cable and feel i am more prone to rotation issues. Maybe someday i will make an L-shaped piece of wood that i attach to my arm and to a cable