This douche said he used to overtrain. I didn't know looking like a prisoner of war was the result of NOT overtraining!
This notion of only been able to train a single body-part with a certain prescribed amount of sets and reps once a week is rubbish. There have been countless lifters that have trained with maximal weights for months on end. They have grown and gotten stronger as a result. The perfect example is powerlifter training for a competition. From about 4 weeks out you should have reached your previous 1RM and for the next few weeks you are lifting over your previous 1RM in order to set a new strength level for your next competition. Another example is just choosing a particular exercise each week and making sure that you set a new 1 RM PR each time you enter the gym.
I challenge you to try this. Each session you train for the next month make sure that in each session you set a new PR on a given exercise. They can be different each time but one thing I would happily place money on is that you will be stronger at then end of that month then when you started. Not only that all things been equal I would be confident that there will be none of this dreaded overtraining bug which will afflict you worse than some tropical disease and strip every ounce of muscle from your body overnight. It just won't happen. The human body can handle anything you throw at it provided you do it progressively and smartly. Do I need to remind you the first bastion of progressive resistance? Milo of Croton.