Talking about the book:
The further benefit to these is when they are used in the no-huddle: The offense can run to the line, line up, call a single, simple concept, and the quarterback chooses where to go with the ball, making the defense wrong, every time. This is in contrast to requiring the quarterback to make lots of complicated checks or audibles at the line of scrimmage or to do that whole everybody-line-up-no-wait-look-to-the-sideline-for-the-new-signal thing. It’s run it and go, and the quarterback is the field general.
On defense the big trend is to take existing defenses, like the 3-4 or 4-3, but to begin using more “hybrid” defenders in the base defense, guys who were maybe considered “tweeners” a few years ago without a true position. These are the linebacker/safety hybrids and the defensive end/linebacker hybrids, who, when facing all these no-huddle or multiple-formation attacks, must be able to both take on a fullback or tight-end at the line, rush the passer, or drop into pass coverage. If you’re going to have any hope of defending a dynamic offense like the one Urban Meyer runs — which is spread but can use power, and can use power but still throw the ball around — then you need to meet that dynamism with more dynamism.
Read the whole thing.