If I had only bit advice for Galen?
Which is doubtful he'll ever see.
But it'd be advice for Galen Rupp and Lukas Verzbicas.
It is advice from a book. I'd been reading advice from
various sources for about 35 years yet this recently
published book (2011)titled "Iron War, Dave Scott, Mark Allen:
The Greatest Race Ever Run by Matt Fitzgerald has a chapter
that's perhaps the greatest secret about the mentality and pushing through that barrier. Galen, Lukas read Chapter 7 "Iron Will" it deals with mental barriers that upon reading the chapter opened my eyes to what compels me to race/train hard through that pain barrier --- to win. This is it. I only wish the chapter was longer but it is to the point and extrapolates why one athlete is able to push through the barrier when we all should be doing it. Great read.
Dave Scott and Mark Allen are both world class (retired) athletes and Chapter 7 pulls apart their mentality more so than what I've read about other endurance athletes. My only
gripe about the book is Fitzgerald lays claim that Armstrong is the greatest cyclist of all time. I don't agree with that.