Today on the First 40 Miles, we’re not made of titanium (well some people are) but most of us experience injury that can sideline us from even getting out on the trail.  We’ll share some ideas that will turn that recovery time into valuable trail prep.  Then, on the SUMMIT Gear Review, Katadyn rocks the water filtration scene with a collapsible, ultralight, dead-simple filter.  For today’s Backpack Hack of the Week, you’ll learn how to get your knife sharp enough to split a hair or a log…