Phedippidations

What is pronation, and why do we need to understand our unique running gait?  I’ve often been told that I don’t pronate.  Other runners have been found to pronate "too much".  What does poor pronation mean to a runner, why is it a bad thing and what can be done about it are all questions answered (to some degree) within this weeks episode.  Also: I run the Charlton Old Home Day 5 miler road race.