Just re-reading Advanced Marathoning by Pfitz/Douglas, and was wondering whether there would be any benefit to running the long run Saturday (so mainly 18-21 miles with some exceptions), and then a medium-long on Sunday, say 15 miles?
Pfitz likes his long runs as progressions up to ~M-10% for the last few miles; so the Saturday run would be faster of the two (and also the longer).
The book does briefly touch on doing back to back hard days, but I don't think it talks about long days specifically in this way.
I've been reading that lots of ultra runner do these back-to-back long runs on the weekend; maybe up to 30 Sat, 20 Sun. Could a similar approach benefit a marathon runner? (although not as far, maybe 35-40 combined, rather than 50 - which seems pushing it.)
Interesting to hear thoughts on this, vs running the 15 miler midweek and spreading things out more