Thanks for responding Mokaman. That's my understanding too, that the elite long-distance guys do mostly long slow, but also mix it up with tempo, hills, sprints, etc. What seems new in the Maf method is doing away with the latter completely until a certain heart rate and pace goal has been reached. If it really works, I would consider that, but it's so much fun running faster, that I'd really like convincing evidence from my fellow recreational to semi-competitive barefoot runners before committing. If it's just a matter of Maffing it once a week, I'm in without hestitation. Why not? It would only involve running marginally slower than I already do on my long run, and a friend has given me his HR monitor, so there'd be no extra expense involved.