No secrets, guys. Renato Canova has been on this site for years espousing the "secrets" to marathon success, and one key principle that is on display with Wanjiru's training is that of alternating a long run of distance (38km at personal sensation) with a long run of intensity (30km at 3:08/km).
Traditionally the elite athlete builds from 2hr to 2hr 40min in training before introducing a focus on pace for the duration of the run, building from 28km to 36-38km.
Of note that differs from a Canova-based system is the brevity of speedwork in regards to volume. The speedwork of Wanjiru reminds me more of Frank Shorter and Rob de Castella, in that he basically topped out at 3 miles of speed work for a session, whereas Canova's athletes often at times venture towards 21km of work, but most at marathon pace or up to 2-5% faster than MP.
It would be interesting to know at what pace Wanjiru runs his quarters and 3k repeats. Does he blast the quarters in 56-58 sec, or are they more along the lines of 62-64. Recovery? Also, the 3k repeats... is he lifting 8:10-8:15's or 8:30's with very short recovery?
Anyway, what this has shown is how phenomenally gifted Wanjiru truly is in that he can approach MP for 30km every other week in training and then run faster come race day for an additional 12km with such limited speedwork. Do not overlook the fact that he seems to work progressions to MP pace on his easy runs (very Kenyan-like), which is quite difficult for a Caucasian to do in training.