Originally Posted by Chas Tennis
What do you mean by dropping the racket? Could you point it out on one of these videos? I see the rackets winding up higher than the head in these videos from reply #12.
They begin with the racket higher, but when I compare Federer's or Nadal's forehand to the average forehand on the tour, I feel like their take back is less circular, more like a racket drop. But, that's an illustration or a visual cue, if you prefer; the point was to bring people get an idea of what this type of forehand look like since some might not be very comfortable using pronation/supination, extension/flexion, radial deviation/ulnar deviation, etc.
To me, personally, it feels like the racket just drops down. However, that's my perception and it's heavily influenced by my personal experience and, unfortunately, it can't be an actual illustration for everyone.
Regardless, the important point was pronation versus supination during the take back
... Again, "take back" is also not clear, but I would say that when both hands split (usually, players keep both hands together before until they are ready to swing; many, for instance, will hold the throat with their off hand), the take back begins. As for when to identify this feature, it's mainly by the end of the take back: as the player is just about to swing.