Grease The Groove is intended for getting really good at a specific exercise. Bulgarian Olympians use an extreme form of Grease The Groove to dominate Olympic weightlifting.

The idea is that you're practicing while fresh, as opposed to working out until fatigued. GTG trains the body to be strong always. In contrast, working out until failure trains the body to be weak once tired. I plan to use grease the groove for pull-ups until I stop seeing improvement. I am continuing to do my cardio as usual.

Just read the companion book to Body by Science. Still pretty persuasive and pretty radical seeming.