Really interesting post . I'm still very much in the novice category for running (sub-to-near 5k) so I won't be implementing this anytime soon but I'll keep it in mind for when I get more experienced.
I imagine it would take a lot of willpower to get going on that second run, probably equally as good for mental toughness.
Cheers.
DE
RE: Running twice a day, why is it interesting?