I would like to ask a question that nags me every time I read an article like this: Why do we assume that we need "free time"? And to answer this, I have to ask another that occurred to me while reading the article: What do these elite players do during their free time?
This is an important questions for programmers and engineers, because we generally enjoy building things. In the context of the article, I take it as implicit that the one thing the elite players are not doing in their "free time" is playing music or that would obviously be a form of practicing.
So, then what is this free time that the elite have and how are they using it? Are they bumming in the front of the TV? Is the formula for success: work intensely for two short blocks and then veg?