By implication, you might feel that no one should coach a sport who actually hasn't practiced that sport. And, while it's true that a great many coaches are, in fact, former athletes, that isn't always the case. I have never executed a long jump or triple jump in my life, but in my area of New York, I am generally considered one of the foremost authorities in coaching those events and have turned out multiple state and even national champions.

Dog Hand mentioned Ed Thorp. I'll throw in Peter Griffin. He never played the game for more than nickels. But, he remains to this day our greatest teacher at least of the theoretical aspects of the game.

Bottom line: Yes, someone who has "done it" often can teach in a manner that someone who hasn't done it can't. But, I would challenge the notion that, in order to be an effective teacher of a skill or craft, one needs to have practiced that skill himself/herself.

Don