I think I can summarize my first experience with the FiveFingers as follows: ow, ow, ow, Ow, Ow, OW, OW, OW, Holy Frickin' Hell, OW!!

There's no question you use different muscles with these shoes on. I'm usually capable of running 3-4 miles with ease and my "long runs" are about 6-7 miles right now. I did 1.18 miles in the FiveFingers.

The first thing you notice once you start running is that you need to change your approach. If you heel-strike on the forefoot (75% of folks do), the sudden lack of the huge heel pad found in most running shoes will be immediately evident. With headphones on, I could hear the shock of the impact reverberate up through my entire body, even over the music.

Once my legs warmed up, I almost naturally started to run on the balls of my feet. I'd strike on the outside edge, and my foot would roll slightly over the toes as my other leg came forward. It was new, but it started to feel natural very quickly. I noticed my stride shorten as well, and my pace was not nearly as fast. Overall, I was about 30% slower on this inaugural run on the FiveFingers.

Where I really noticed the difference, however, was in my lower legs and feet. Since your heel just brushes the ground, your calves end up carrying the weight of your body on each impact. And even though I try to force myself to run on my midfoot when in regular shoes, the sense that your lower legs are shouldering even more weight in the FiveFingers is more pronounced.

After about a half mile, my calves were sore. By 2/3 of a mile, I could feel it in my achilles tendon. At one mile, everything below my knees was awake and trying to have a conversation with me. Just shy of 1.25 miles, I had to stop.

I could have run for a lot longer, but not in these shoes. What's intriguing to me is how I should interpret the muscle soreness. On the one hand, it'd be reasonable to determine that the cushioning and padding added to shoes over the years served a purpose, and that it's no surprise why no one walks around barefoot. It just hurts; why would they?

However, from what I've read, my experience is normal, and that most people -- even long distance runners -- discover that barefoot running exercises muscles that have never been put to use on a run and hit a wall very quickly. The pain, it is argued, is from dormant muscles being activated and that continued barefoot running will simply lead to stronger feet and calves and, with it, more stability and less pain while running.

Obviously, having bought these shoes, I tend to subscribe to the latter view. I wouldn't have forked out the $80 if I didn't think there was a benefit. But it's obvious it will be a while before I can put some real distance on with the FiveFingers. I'm willing to give it a try, and will work up slowly. Whether I'll experience the benefits as I do so is still not clear to me.