How is This Not HIIT??

John Hackleman is an interesting and talented teacher and although we've only spoken a few times every interaction with him I've learned something valuable. I don't think we've seen the depth of his knowledge. His training stories concerning Chuck Liddell, his own competitive experience, and his thoughts on self defense give nice counterpoint to grappling only systems.

Take a look at the literature on HIIT

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088375