Here's a really interesting article I found on the " vision and break" principles espoused by Hafley and how they came into being.
https://www.elevenwarriors.com...yle-of-zone-coverage
"How do you limit explosive plays?" Barnes asked the crowd rhetorically. "Limit busts, limit lost leverages – make sure you’re guys are running to the ball, and limit missed tackles. How do you do that? Let them play fast. If a guy has to think, he’s going to miss tackles. If a guy has to think, he’s going to bust. If a guy has to think, he’s not running to the ball. Make sure they know what they’re doing."
One of the issues with the Joe Barry defense is that there were too many
"If this/then that" decisions to be made on the fly. And that led to communication breakdowns and busted coverages. The Hafley method aspires to remove that uncertainty and let the athletes shine. Looking forward to seeing it in action