http://headrush.typepad.com/creating_pa ... an_ex.html
In the book The New Brain (it was on my coffee table) Richard Restak quotes Ericsson as concluding:
"For the superior performer the goal isn't just repeating the same thing again and again but achieving higher levels of control over every aspect of their performance. That's why they don't find practice boring. Each practice session they are working on doing something better than they did the last time."
So it's not just how long they practice, it's how they practice. Basically, it comes down to something like this:
Most of us want to practice the things we're already good at, and avoid the things we ****** at. We stay average or intermediate amateurs forever.
Yet the research says that if we were willing to put in more hours, and to use those hours to practice the things that aren't so fun, we could become good. Great. Potentially brilliant. We need, as Restak refers to it, "a rage to master." That dedication to mastery drives the potential expert to focus on the most subtle aspects of performance, and to never be satisfied. There is always more to improve on, and they're willing to work on the less fun stuff.