Tinman,
Thanks for the reply. However, I thought you would have realized by now that you shouldn't make assumptions about a person based on a single sentence you read on some message board.
I have, in fact, heard of Dr. David L. Costill. I read his opus "A Scientific Approach to Distance Running" back in the 8th grade. This was also when I was lucky enough to pick up a second edition hardcover copy of Lydiard's "Running to the Top" in a used book store and began testing out his theories of 100 mile weeks and weekly 20+ milers (during the base period) in my own training.
I was in no way questioning Costill's integrity or legitimacy as an exercise physiologist. Rather, I was simply interested in the science behind Costill's alleged proclamation. Apparently, I just need to go back and re-read his book.
In regards to your suggested 5k-10k training and your citations of a number of elite athletes' training regimens, I agree that when one has already added v02 max workouts and races to their schedule proportionally-distributed doubles are probably the way to go in order to maximize recovery. However, my question was in regards to the BASE building period of training. Would you suggest a number of 1:30+ runs each week during this period, in order to develop greater strength?
Finally, why would I even be on this board asking questions if I already "have my mind made up"?
Thanks again for your contributions to the discussion.