IMO, weight has nothing to do with it. Intensity is the whole game. You can get the same intensity by using less wt, lowering and raising the bar very slow and controlled, with strict form----or heavy wt, with explosive, fast(safely) movements. Mix it up every couple of weeks. If my joints hurt on a particular movement, than I tend to favor higher reps. Military press, hurts if I go to heavy, so instead, a little less wt, and slow strict form at higher reps.