neck stiffness when doing rear deltoid flies

[claycat]

Everytime I do rear deltoid flies on the machine my neck gets real tense, especially up the right side. The stiffness continues into the day.

I do 3 sets of 12 at 45#.

Am I performing it wrong to cause the tenseness? My form seems fine to me.

[FlyingV]

Without seeing you in action it's hard to say if you're performing the move wrong, but my guess would be that because you're using a machine, and presumably sitting down while doing so, the burden of stabilizing your body through the movement is falling, disproportionately, on your upper back and cervical spine. One option would be to change over to free weights for rear delt development, something where your feet are on the ground supporting you, and the necessary stabilizing and balancing forces are spread out over more of your body than would be the case when you're sitting on a machine.

[claycat]

Thanks, I will switch over to free weights and see how that goes.