Trail Running in Vibram FiveFingers
This is me trail running in my Vibram FiveFingers -- these are my absolute favorite shoes EVER. They are basically a glove for your foot (the shoe has individual pockets for your toes). I'm prone to injuries from running/hiking, I have yet to get an injury from these, that said, these shoes do require more muscle effort as your muscles absorb the impact as they're meant to.
Since wearing these I've become a firm believer in running with barefoot mechanics, regardless of what shoes you wear, this means landing on the balls of your feet, never on the heel! The huge air pockets in most running shoes promote landing on your heel, which means landing with your leg extended straight -- this is unnatural and why we feel impact in our knees/hips; land on the balls of your feet and your leg becomes a spring, absorbing the impact via your calves.
Barefoot running is about running as gingerly as possible on the balls of your feet in a 'forward' motion (rather than a hopping/bouncing motion).