Overtraining is a emotional and a physical disorder that can be prevented with a little bit of awarness.  Once you realize what the symptoms are and the ways that you can prevent them you are going to be way ahead of the game.  This disorder can and will cripple your performance in almost every way that you can think of and effect every aspect of your life.  If you want to get killer abs you better know how your training should be timed.  Too much work in the gym will stall your entire program.  Volume can be your enemy too.