Here's a brief post about this:
"But, it's not just that trying to describe your performance can disrupt it. Skilled performers often have trouble putting their actions into words in the first place. That's why those who perform at the highest levels should think twice about teaching their skills to others. When a scratch golfer in my lab, for instance, was asked to describe a putt he just took, he replied, "I don't know, I don't think while I putt." When your performance flows largely outside of your conscious awareness, your memories of what you've done are just not that good."
Being good at
something, and understanding what it means to be good at something
are two different competencies. Evidence of expertise in the former should not count as evidence of expertise in the latter.
this is of course true : when I meant Sampras was an expert, I meant comparing to most MTFers, I didn't target a very high goal
But the best experts should be coaches because they had to practise their skills to understand how players who are not them work ... and also their skills to explain things about that.
And another problem with guys like Sampras or Guy Forget, players of the old time ... is that the game has changed a lot comparing to their time. I'm always fed-up when I hear Guy Forget because for everything a modern player does, he has a referrence to what older players did ... which led to saying things like "Federer should do against Nadal what Stich did against Muster" or that kind of things
But still apart from that, even when people are really experts, it doesn't mean that what they tell us is really the result of their expertise : first they may not want to reveal their secrets (here I mostly think of coaches and current players), secondly they'd rather tell us what was dictated by other goals like publicity and entertainment ...
and that's my main concern with these "public experts" : I don't pretend at all to know better about tennis than Mats Wilander but I can surely pretend to have a more objective and serious talk