Posted: 19/06/2014 at 08:34
Hi HKPL, Not sure that I can advise you specifically, but from my own experience, my best HM's have been off much lower mileage, running just 3 - 4 times per week, but apart from the recovery run, I made every run count (which means getting good rest!)
Basically, per week I ran:
one LSR (about 16-24k, so occasionally I ran slightly over distance)
one very short recovery run (5k),
one flat 'interval' session, (intervals were .5 miles or 1 miles each total of 3 - 6 miles at pace, but not completely flat out, with 400 metre rests)
one hill repeats (.5 mile warm up, then up to 10 x 300 metres up hill, with slow jog down. Again, the intervals were not necessarily flat out, but they were an effort -and I didn't start with 10!!! )
As you can guess, I didn't start by running all those intervals, but I built them up gradually, so that I was doing that sort of weekly run for the last four weeks of training prior to taper.
I also did Pilates to keep the core strength up.
Hope that helps, or maybe gives you some ideas to think about.