Jonathan Gault recently caught up with Puskedra who reveals he did 130 mile weeks (all in singles) + an hour of biking each day to get ready for Chicago.
http://www.letsrun.com/?p=127746
Here is a typical week of training:
Monday: long warmup, track workout -- either 12 x 1k at 2:40-2:45 with 1-minute recovery or 8 x mile at 4:25 with 2-minute recovery
Tuesday: hilly 22-mile run
Wednesday: 13 miles easy and strides
Thursday: 40-minute warmup, 90-minute hilly fartlek, 10-minute cooldown. Approximately 23 miles total.
Friday: 13 miles easy and strides
Saturday: long run, 24-28 miles with the last part close to marathon pace
Sunday: 13 miles easy