I would say it is only possible to overtrain in the context of that at some point you cannot keep up with your schedule if strength and very heavy weights is your game. Even then, it's only really that you cannot lift maximally every workout. Who knows if it isn't still beneficial - because most people will slow down if they can't hit their targets every workout.
If you train more bodybuilding style, it's more endurance and the human body can go fine on that.
There are people who run for what seems forever, we turn up for an hour a day and talk about overtraining
It's only when you take your fat, hyperventilating ass and go on 1500 cal a day, training 6-7 days a week that you realise that all that heavy breathing and gassing on three rep sets was pathetic
