In 1990 the performance of Hammer weighting became apparent. It was used by the unknown second tier junior, Pete Sampras, who was never as good as Courier or Agassi or Chang. As soon as he got Hammer weighting, he won the 1990 US Open, using a 16 ounce racquet that had 3 1/2 ounces of lead added to the top of the grip of a 12.5 ounce 1970's Pro Staff.
I was modifying 1970s aluminum racquets with it, and getting spectacular results. In 1990 that type of weighting was given to the two little girls, Venus and Serena. They were kept out of junior tournaments. The reason was so as not to call attention to themselves, or to the amazing performance of these racquets.
They had been given an advantage. Pete Sampras had it, but the racquets were kept off the market. And you can't buy or obtain the same racquets pros use today. That policy was started in 1990. Before that, you could buy the same racquets pros used.
This year, someone who is probably supposed to be smart and important believed like you that it wasn't the racquet and changed the weighting in Venus and Serena's racquets. Venus loses in the first round and Serena loses early. Embarassing.
The reason they both lost was because their shots didn't go in the court. Venus made 65 errors. Serena said she didn't have any feel for the ball. Roddick didn't have a clue why he lost. He looked like he felt good.
The reason was low polar moment of inertia, as opposed to high polar moment of inertia. In other words, the weight was in the center of all their racquets near the string bridge, which is a different weighting theory from the last 15 years.
Jack Kramer used a 16 ounce racquet that had a very heavy handle, but the real secret was high polar moment of inertia. He had a lot of weight in the handle and weight in the head. Today, by optimizing the polar moment of inertia, which was Prince's theory, we can make 345 gram racquets that have the same dominating performance as Sampras' or Kramer's racquets, but you can't buy them; they are supposedly bad for the game, and yet, Kramer used that type of racquet.