I can tell that I'm getting stronger. I felt really great during most of my 13 mile run on Saturday. At the 7-8 mile markers I felt like I was in heaven. It wasn't until I started to dehydrate during the last 3 or so miles that I felt tired. I seemed to have a higher energy level over the weekend and yesterday. It will be interesting to see how my 8-mile rest-medium run goes tomorrow.