Today I went to the local track which is rubberized asphalt, and it is a fairly rough surface compared to roads and sidewalks. My goal was to go two miles slowly, but once I started, I felt so good that I picked up the pace to about a 7:30/mile. Up to now, all my barefoot training had just been easy jogging.
I was feeling great at about 1.5 miles, but the surface of the track was starting to wear on my feet just a little. At 1.75 miles, my feet were still fine, but I knew I should stop after 2 miles. Coming around the last turn, I felt something wet in between my toes on my right foot, which I assumed was just sweat. Unfortunately, when I stopped and looked down at my toes it turned out to be blood. I rolled my eyes, because I knew I had pushed it just a little too far, and I had let my goal get in the way of making good decisions. Fortunately the blood was from nothing more serious than a blister.
If I had been running on plain asphalt or concrete, I have no doubt that I could have run much further than two miles, and at a much faster pace. I specifically use this track, as well as another gravel track, because the surfaces are rough, and challenge me to develop better technique.