From Scott Saifer at CyclingNews.com:
"I happen to know the exact program that Freddie Rodriguez used the year he made the jump from the US Pros to the Euro Pros because my business partner was his coach at the time. I think you'll be surprised.
First, all the off season riding he did was at 70-80% of maximum heart rate, easier if he was tired. He started out with rides of less than one hour in October and added 20 minutes per week until he was doing six hours every day. By the time he finished in February he was doing 25 mph average on flat and rolling courses for six hours, and he was bored and lonely.
His coach let him do exactly one sprint in training before the stage race that catapulted him onto the international stage. That sprint was for confidence, not for physiology. No intervals. No intensity."
So what this tells me is that some of these guys are freaks and don't really need intensity work.