Not sure if this clarifies the discussion, but here is something that Renato wrote:
The first time that I heard about this system (intensity before quantity, for marathon runners) was in 1972, from Belgian Gaston Roelants, one of the greatest runners of the period. Roelants was record holder of steeple, then moved to marathon. At that time, he was already old (35 years), and, when he explained me his program, I also asked him "why speed before endurance ?". His answer was : "For me, running long and slow is very easy, after many years of activity. What I lose in short time is the capacity of running fast. So, for me it's a mistake running many km slowly before developing speed. When I'm able to run 10 times 1000m in 2'48" recovering 1 min, for me is very easy, in short time, running 20 km at 2'58" and full marathon at 3'10"".
Going on with our experience, we applied this system with all italian runners, from Pizzolato to Poli, from Bordin to Bettiol, from Baldini to Caimmi to Giacomo Leone now.
Currently, long and slow run doesn't exist in a modern training program for marathon. Really, about 40-50% of the global volume is done with slow run (under 80% of Marathon Pace : for example, if you run a Marathon at 3'10" per km, 19" every 100m, 20% is 38", so running at 3'50" isn't a work, but regeneration run), but TRAINING FOR BUILDING YOUR PERFORMANCE BEGINS WHEN YOU RUN OVER 90% OF M.P. (from 3'30" going faster). Specific workouts for marathon are WORKOUTS LASTING MORE THAN 1:30:00 at a pace of 90% or better, and in any case never shorter than 22/24 km.
In our methodology (the same for Spanish runners), at first we try to lift Anaerobic Threshold (about 60-45 days before the marathon, difference between AT and AnT may be about 10%), then, maintaining the same intensity, we try to develop specific endurance.
In the modern concepts for middle distance, WE TRY TO DEVELOP THE POWER OF OUR ENGIN (that is Anaerobic Endurance) in the first 2 months of preparation, then TO DEVELOP SPECIFIC POWER-ENDURANCE GOING TO THE EXTENSION.
This is a system not only for marathon, but for all long distance. Of course, is yet possible to use the other system, but the capacity of intensity cannot stay long time without beeing stimulated, and is a mistake to permit that your quality can go down too much.
My interpretation of what Renato wrote is that traditional base training starting with and emphasizing long easy distance is not what he uses with his athletes. Some people will say "Well it's still aerobic first, just not long easy distance first" and I have no argument with that.
Here is something else that he wrote about his hill circuits:
I explain you the circuits that Shami uses. The phylosophy of circuits for strength endurance is always the same, but the stations depend on the situation of the place of training. In the case of Shami, he carries out his circuits in Eldama Ravine, a village 120 km far from Eldoret, with a lot of hills.
His circuits, that he must carry out at max intensity, are the following :
a) 120m bounding (flat)
b) 300m running fast (flat)
c) 20 sagittal splits on the place
d) 60m sprint climbing
e) 40m skipping climbing
f) 60m sprint climbing
g) 40m heels-to-buttocks climbing
h) 60m sprint uphill
i) 40m bounding climbing
l) 100m sprint climbing
m) 10 squat-jumps on the place
The circuits is carried out on a small hill, with 420m of flat rough road before starting 400m of hard hill. So, all is about 820m. After finishing, the athletes of the group WALK for about 300m downhill, going back to the start. One loop is about 1,120m.
Of course, if you have other options, you can change something. For example, with Rita Jeptoo I use something a little bit different : when we are 4-3 months far from the competition, her circuits are uphill only, for about 600m, and there is more attention for technical exercises, done at high intensity, while the run (about 80m climbing between every station) is at 80% of max speed. In this case, the current focus is for increasing strength and specific technical ability when tired. So, we use Aerobic Resistance in order to support STRENGTH ENDURANCE. Instead, during the last 2 months, we go to qualify the intensity of the sprints, and the exercises lose part of their importance. The final focus is to use strength for supporting AEROBIC POWER.
We use this type of preparation ALWAYS, after every Marathon, for recovering the personal level of strength, that during the specific period of preparation for a Marathon the athletes go in part to lose. But, in the case of Rita running Boston, that is a very hilly marathon, we maintain this type of training till last period, because to have strength endurance is one of the most important goals in order to finish with high speed (last year Rita ran 16:15 between 35 and 40k, and was the 4th performer in all the race (better than the top 8 men) from 40 to the finish). Don't forget the "heartbreak hill"....
Again, my interpretation is that Renato is not emphasizing long easy distance in the buildup to a marathon. The circuit stuff seems in direct contrast to something I read about Bill Rodgers saying that when his vertical jump was almost non-existant, he knew he had trained well and was ready for a good marathon.