If you can ride 100% 7 days a week than is that overtraining? How about if you can ride 100% only 2 days a week???
Point I am trying to make is the same one Landis does. If your body cannot handle the workload you give it and its to the point of injury than you were undertrained for that effort. You cannot start out doing 100% for an hour a week when riding but can bulid up to it. At some point you will cap though and it might be that you only have one day a week where you can give 100% effort. Maybe you are a beast and can give 100% effort 4 days a week who knows.
(trying to be general with the effort here)
I know guys and gals that train very hard 5 days a week. They are good CAT 1 and 2 racers and very fit. I also know guys and gals that train hard 1 day a week and are also CAT 1 and 2 racers. Different strokes for different folks.