Did 4 miles on the treadmill today -- about 1.75 miles of that was running. I used the "interval" program which automatically changes between a walking and running speed every 1.5 minutes or so. Really works for me as I would not be disciplined enough to do that on the road, especially without music. With all my favorite tunes and a set program, I do very well. I know most people hate the treadmill, but it works for me. :-)