Over training: Not impossible, but probable. Over training can be a catch phase; some can adapt more than others. But each of us has a personal limit to the stress allowed in workouts. And the full recovery time from workout to workout. If not fully recovered from the last workout, than the chance of over training is greatly increased. Making poor progress, or no progress at all, feel tired and each workout becomes more like a chore than something you are looking forward to...over training perhaps?
Giving top Pro's as an example (Coleman & Cutler), of any thing, is always a bad idea. If you were to record their every move, 24/7, you might find that it's quite different from what is printed or shown in a video on their training, foods they eat and actually workout time, and the weight used on exercises, in the gym. One true thing is that after any contest, reaching their peak BB'ing condition (which they can only hold for perhaps 3 or 4 days at the most), they are in a very poor degree of personal health...and will usually crash. Both physically and mentally.
Good Luck