training for strength

A natural athlete should train for strength and size will follow it is often said. Does this mean they should follow something like the 5x5 program? And does it also mean that a higher rep range (10-12) would be a waste of time. I´m also quite confused when it comes to volume. Ian King says most people are overtrained and should reduce frequency and volume. Don Alessi says overtraining is very rare and often an excuse for people not to work-out so hard, and perscribes high volume workouts with a twice a week frequency.