This comes up pretty frequently, particularly w/ the shrugs. You can probably even find a thread a few pages back. Long story short, adding in power shrugs has been "okayed" so long as you don't turn them into a core lift and don't start trying to do 5x5 pushing PRs w/ 'em b/c they'll start cutting into your reserves needed for squats/bench/row/DL, etc. I do a few sets of power shrugs at the end of my M & F workouts. Or, did, when I was running SF 5x5. If anytihng, if you're having a particularly tough week and feeling weak, etc., drop 'em or reduce volume, etc. so you don't F w/ the rest of the program.