Each year, between January 1, when he resumed training after a post-Ironman break, and April 1, Mark never allowed his heart rate to exceed the Phil Maffetone–imposed limit of 155 beats per minute.
Curious if this approach is still in favor. The book didn't go into great detail about it - but this article from Phil has more depth: https://philmaffetone.com/want-speed-slow-down/ and here is a good review of ithttps://gonefora.run/does-maf-training-work - sounds like something to look into.
