I have not followed the Maffetone method I referred to in September as much as I wanted to. Mainly because I had a couple of marathons in there and was not going to keep my heart rate below 128 in those races.
I have been working on it off and on and trying to run more consistently. Sunday I did a test on my progress. In the last workouts (none since early November) that I did in this method, I found that my pace would be under 3.5 mph after the first hour and I would have to switch to walking where my body is much more efficient (I can walk over 4 mph for a long time without my heart rate going up).
My plan was to continue running until I got under 3.5 mph or two hours, whichever came first. At the end of 2 hours my speed was still 3.7 mph and most of the time it was 4 mph or greater, so I am definitely making progress.