Experiment-

   So it is difficult for some of us runners to ever consider walking at all during a run...why? Because it's a run not a walk!? However, today I decided to experiment with a walk segment. I am getting older so perhaps it will benefit me to try. I did nine minutes running and one minute brisk walking. I did this for 18 miles and I am very pleased with the results! My last three miles were my fastest! So I am thinking about using this as my plan for the marathon.
  It was very interesting to see how the body was able to respond and use the walk segment in a positive way. So the experiment was a success. The long run in the books, and now a rest day tomorrow! Hope all is well with you!