Tried the Jeff Galloway walk/run method which I'm doing for the next 12 weeks leading up to the half marathon. I think i ran too hard during the run parts. Or didn't walk often enough?

Anyway, did 4 mile in 43.34 (for me that's good), but then I just died on the vine. Legs crapped out and died a whimpering cry-baby death. Still not a bad time considering the walking, so as a theory, I can see how walk/run works. (At least 1 minute walking per mile)