I love running uphill barefoot, where I run into trouble is on the downhill side of things. A couple of weeks I was out of town and did a uphill run for about 2.5 miles and it was great. I turned around and ran back down and by the time I hit bottom I had a good sized blister under both my balls of feet. Mind you this was on some pretty rough chip-seal pavement. Have not perfected my downhill form yet. We haven't to many hills in Winnipeg to work on that part of my running either.