How is that?
I did this route a couple of weeks ago and felt great. Today, I did it but not easily.
Maybe biorhythms do have something to do with it. According to the calculations on a couple of web sites (here and here), they all agree that my physical rhythm is low but rising. Which would make sense.
The charts also showed that two weeks ago, it was much higher. Which also makes sense to have had the great run at that time.
Have you mapped your biorhythms to your runs? How do they work out? Does it make sense?