I happened to come across some blog posts by the “Lazy Marathoner” for the LA Times. She consulted with Dr. Maffetone about training after running an eight-hour (!) marathon.
So after running at a low heart rate for some time, she then ran a half-marathon. But this took just under 4 hours! In my book, this equals no progress.
I keep coming back to my same criticism of the Maffetone method – I think it only works well when a person is already running fast. So if someone can run 6-minute miles and then they slow down for their training to 8 or 9 minute miles, then yes, I think they can benefit.
But if a person is running slow or doing a combination walk-jog, then continuing to run slow doesn’t seem to help much. It’s like there is a certain threshold of speed needed, and when the running pace falls below this, it becomes very energy inefficient.