So, 8 weeks is 56 days.
I would suggest that the 56 days could contain:
1. 6 x Progressive 10 milers
I mentioned these before with an outline time of 61-63 minutes, consisting of a continual gentle acceleration through from 6:45/mile to maybe 5:50/mile for the final mile.
However, the first two efforts should be scoping sessions where you build the session from the end backwards, eg
a) The first attempt may be a pushed along, but comfortable, first seven miles with all the focus on finishing with a last 3 miles in maybe 6;15, 6:05, 5:50.
b) The second attempt would be similar but with the focus on finishing with a last 5 miles of maybe 6:25, 6:20, 6:15, 6:05, 5:50
The final 4 sessions would then involve the full 10 miles being progressed along from around 6:45 for mile 1.
NB The paces are not 'paces to be hit' but just to give a rough idea of the effort levels involved. Remembering that this isnt a punishment regime, no session should leave you dreading the thought of the next time. When run correctly, you should be buzzing at the end and really be looking forward to doing it again.
2. 3 x Fast Finishing 22 milers
As previously described, this is where you would set out for a very relaxed 18 miles at around 8 mins/mile and then look to ramp it up over the last 4 miles with a finish looking something like 7:30, 6:40, 6:10, 5:50.
It is perfectly suitable to use a 20 mile race for one of these sessions if you have access to one.
3, 5 x 18-22 mile LSRs
You are looking for these to flow rather than feel like an effort but no need to artificially slow them down provided that the legs are happy and there is no noticable breathlessness. You'd probably reduce this by one because of the planned ultra.
4. 6-8 x 13-16 mile MLRs
Again, these should be at a similar effort to the LSRs but they are also ideal to use as low glycogen runs. You can simulate reaching 22 miles without getting anywhere near 22 miles by deliberately starting the runs on low glycogen by not eating carbs for something like 8-12 hours before (not as difficult as it sounds).
You are then encouraging the fat burning adaptation required without the associated muscle damage associated with running hard for 20+ miles to achieve the same level of glycogen depletion.
5. 8 x 5K runs at approx 10K pace (parkruns or similar)
A regular weekly effort at around 5:45-5:50/mile which feels comfortably hard. One or two of these can be converted to full out efforts if it feels appropriate on any given day but most should be within a comfort zone.
And that would give 28-30 'effort days', around which you would fill in the other 26-28 days with easy as you like general running. Some days it may turn out as 10 miles @ 8 min/mile, another day might be 10K @ 9:30/mile but the key thing is that there should be no mental effort involved and nothing should be strained at any point.
You may also add further easy runs as 'doubles' on the effort days but only if a) You have time and b) You are recovering well enough between sessions.
Will this provide sufficient mileage? That isnt really important. By doing the key sessions in the approx quantities outlined you will default to a respectable mileage, the volume of the additional easy runs will, to some extent, depend on how you are responding between sessions.
Dont be afraid to bin a session or take a rest day just because of some notional weekly mileage target, a week is not some magical unit of work anyway - it is the totality of the 8 weeks that is more important.
When racing during this period, you would generally just substitute for one of the sessions, eg a HM race for a progressive 10 miler.
Edited: 27/12/2012 at 16:26