Posted: 09/01/2015 at 10:29
Dara, it depends on the sort of experience background you have to how you start, and how to progress things. If you are an experienced endurance athlete, returning to Hadd type principles, then I would suggest the progression would be very quick eg.
Block 1 - all easy stuff ( less than 75%), building time-on-feet
Block 2 - add in some sub-lt (~80% nd build to 70mins
Block 3 - marathon specific (83% / MP runs) and some 20milers+
For less experienced runners or if you have turned to Hadd because of a particularly weak translation of race times, then the start would be the same but progression would only take place when ready.