When Mario and I reached the car after the LONG day of our Mantario trail run, the first thing he did was take off his running shoes to slip on a more comfortable pair. They looked pretty sweet and I asked him why he hadn't done the run in them. His took one off and bent it in half to demonstrate how flexible the sole was. "These shoes are good but they're like going barefoot - not suitable for such a run" he said in his characteristic eastern european accent. In response, I pulled the mud-encrusted trail runners I had travelled the 40+ miles in the day before, bent them in half both ways, and said - "Oh really?"
I had worn a pair of inov-8 x-talons - aggressively treaded trail oriented shoes that weigh less than a pound for the pair (212 grams each). They use technology that intends to mimic and support the mechanics of barefoot running - allowing for the arch and calf to play a much greater roles in cushioning and propulsion.
I first learned about barefoot running some 6 or 7 years ago after my brother touted it's benefits after reading some research about it (he always seems to be one step ahead of me with this stuff). I briefly toyed around with the practice - going out once a week for a three mile run along sidewalks in San Diego. My feet gained some slight callouses and my calves were sore for days after each jaunt, but i found it difficult to push the mileage much beyond what I could cover in half an hour. When I moved to NZ in 2005, however, i gave it up as most of my running was on trails - I wasn't willing to go short enough distances at slow enough speeds to allow my feet, tender from 30 years of wearing shoes, to become tough enough to handle the terrain.
But after joining a team for the 2006 Primal Quest that was sponsored by Inov-8 shoes and getting a few pair, I discovered the next best thing - footwear that let me run like I was biomechanically meant without necessitating a high pain tolerance to sharp objects. I've been running in Inov-8's, and only Inov-8's, ever since. Old knee, hip, and lower back injuries that were aggravated (and probably caused) by running have gone away. My ankles and feet are undeniably stronger and healthier.
While running in such 'invisible' footwear takes time to grow accustomed to - muscle memory needs to develop, gait needs to change - it will be worth the investment. There's loads of research backing this up - some of it starting to make its way into mainstream media. I'll list a few links below and then leave it up to you to make your own decisions.....