Improving muscle size (hypertrophy), endurance, flexibility, suppleness, or explosiveness is achieved by optimizing how the nervous system engages muscles.

“If your goal is to build larger muscles, there's a way to use your nervous system to trigger hypertrophy to increase the size of those muscles. And it is indeed controlled by the nervous system. So you can forget the idea that the muscles have memory or that muscles grow in response to something that's just happening within the muscle, it's the nerve to muscle connection that actually creates hypertrophy. I'll talk exactly about how to optimize that process. In addition, if you want to improve endurance or improve flexibility or suppleness or explosiveness, that is all accomplished by the way that the nervous system engages muscles specifically.”