Kramer,
What is your reasoning behind the longer run once a day philosophy? I followed that sort of schedule (13-16 miles every morning with 4-7 in the evening) this summer and thought that I became really strong. later on in the summer i threw in a couple of 10/10 days just for kicks and found them to be very easy. Whereas I was running consistent 7's or so with the longer one in the morning, I found that I dropped to 6:30's or so very easily on both 10 milers in a day.
Do you think it is better to go really long (15-16)in one run a day at decent quality with a short second run at a very easy pace, or go medium-length(10/10)twice a day at a faster pace?
I guess I feel that going longer once each day gets you in shape to where 10/10 feels easy, while if one were to just do 10/10 all the time, they wouldn't feel very comfortable going 15/5. Just some thoughts.