In one of those six-degrees-of-separation stories that I'm finding are pretty common in tennis, Reka Zsilinszka of Fayetteville North Carolina works with the tennis professional at Country Club of North Carolina in Pinehurst, where my brother was an assistant superintendent of golf until three years ago.
Zsilinszka has told me she doesn't get there daily, as it's an hour's drive one-way, but this story in the local Pinehurst/Southern Pines newspaper mentions a method of tennis training that I've never heard of--concentration on the sound of the ball meeting the racquet.
But what the reporter didn't uncover was the fact that Zsilinszka has played piano for six or seven years, before she began taking tennis seriously, which makes this unique emphasis on sound especially appropriate for her.