Oh, come on. Meditation is not the way to "exercise willpower muscle" (running is the way to do so).

Meditation is the way to learn that your flow of thoughts is not you, it is mere side-effect, a smoke from an engine, a screen-saver, or just idle-running.

Yes, the practice of meditation is beneficial for will-power and self-control, but it is not the goal.) Goal is realization that what you think you are, is just a running total of all previous conditioning, and the ''real you'' could be "seen" is in an instant between two thoughts.

Any good ''eastern'' teacher will tell you that.