Below is Mr. Canova’s basic philosophy as I see it along with my own HR ranges for intensity reference. My LT (functional threshold or 1 hour race intensity) is ~175. My AeT (marathon intensity) is HR 160-165.
Introduction period: 3 weeks. Build general fitness with long runs, weight training (chopping wood works too:)) and short hill sprints. HR would fall in the 130-150 range.
Fundamental period: ~8 weeks. Build to maximum volume first with a low HR of 140-150. Hold volume with a very gradual increase in intensity. HR would be mostly 140-150 with gradual increase in volume of running at 'tempo' effort or HR 160-173.
Special period: ~8 weeks. There is no cut and dry switch to this period. It happens very gradually as intensity increases in the fundamental period. Training simply evolves into this period. The two physiological focuses here:
A) Biomechanical support- increasing the distance of the hard long run. HR 140-165.
B) Metabolic support- The goal is to utilize fat at faster paces. Long intervals approach ~95% of goal pace. Then short intervals are run at 102%-105% of goal pace with an increase in total intervals that gradually evolve towards the length of the long intervals (~10-13 miles total). So here you see an evolution. IE: start off with 10 X 400 at 95% of goal pace and eventually build to 10 X 1 mile at 102%-105% of goal pace. Tough! HR on the 105% intervals would be ~165-175.
Think of this as a funnel where the volume of moderate intensity is extended first, then the intensity is raised while keeping the volume. At the end of the funnel you gradually come in to the specific period.
Specific period: The length of this period is based on the athlete’s development and their ability to absorb the training (one rule I have always followed- if you can't recover from it, then don't do it. Remember that recovery is more important than the training). A little prediction, or "art of coaching" is needed here based on the athlete’s history and goals in order to get them to the start line at the end of this period. Tricky.
In this period the overall mileage is reduced, rest and recovery become a primary focus as the volume of specific (goal pace) training is extended in two directions:
A) Run more repetitions at goal pace. HR 160-165.
B) Extend the length of the repetitions. IE: Start with 4 X 2 miles at goal pace with a rest interval run only slightly slower than goal pace (IE: 800m at ~45”-1’ per mile slower than goal pace). The rest intervals should also decrease in length relative to the work interval and increase in speed. Then build this run to maybe 5 X 3 miles at goal pace on 800m rest at just 30" slower. This would eventually evolve in to your long run of 18-22 miles with nearly all of it at goal pace. HR 160-165.
C) Rest days take as much importance as the hard runs. 2 full days of recovery running is placed before and after each hard session.