Rear deltoids HELP

[SmallBallsBigGuns]

true, my bad, but if you over-work muscle you won't necesarily get nervous system failure but you could be causing too much trauma to that particular muscle resulting in hindered gains, but as you said not necessarily overtraining per se.
SBBG

[NormalJoe]

Right on, that's what I meant by over training, as in just that muscle group, not over all. I lift EOD and have been doing a 1 hour cardio 1x a week on a day off so I still get 2 full rest days.