About 2 years ago I put together a training routine that included the treadmill. The trick to those workouts was to count my steps during the runs to make sure my turnover rate was up around 180 steps per minute. This is something I read about in one of the 18 running magazines I subscribe to and I thought the best way to be consistent with the turnover rate was to use the treadmill. I was right. It took my 5k time to sub 18 minutes and I felt like I was floating during my long runs. Very good stuff.