Pressure. Speed is good too, and impact with pressure typically gets them off, going on, just pressure from like a pry bar across the tie rod end will generally get it. DO NOT GREASE THEM!!!! That makes it to where the friction won't hold them back, and you will not get them tight. If re using the tie rod end, lube the threads, but not the contact area in the spindle.
It really isn't loss of strength, it is loss of resistance. The pressure increases friction, which resists the motion, that is all it is to it. Less resistance, the pivot spins, more resistance, the pivot stays stationary, allowing the thread to put tension on the pivot. Think of the pivot ball as a bolt, and the back side is blind, how would you hold it from turning? Pull on it to make friction.