In modern tennis serve doesn't almost count - Part 2: evolution of racquets

The marginal relevance of the racquet “modernity level” could be superficially demonstrated simply regarding what amazing heights has achieved Roger Federer with a dated model. More specifically, we could start our analysis considering that the 80% of the serve efficiency is determined not by the tool details but by the rotation speed impressed by the player arm. It’s the so called “angular momentum”, obtained in the service movement with the trunk rotation (reaching its maximum in the point of greatest elbow bending) and the shoulder rotation. Passages from wooden frames to aluminium or fiber variations, the evolution of strings from natural bowel to synthetic matherials, the new oversized racquets hasn’t seemingly modified the potential serve speed. In a 1997 experiment conducted for Tennis.com, Mark Philippoussis produced two highly comparable serves with a wooden racquet and with the model he was using then.
The differences in racquet design introduced anyway a series of innovation to the game, changes that could coherently explain the data before presented. Wooden racquets, or the first aluminium models, like the one used by the pioneer Jimmy Connors, had a weight of more or less 450 gr while the modern tools weighs about 300 gr. As confirmed by studies focusing on baseball, conceptually extensible to tennis, is not an alleviation in se. A lighter racquet can be moved with increasing speed and rotation, but a quicker speed means a subtler margin of error and affects the ball behaviour in terms of intrinsic speed and rotation on itself. Daniel A. Russell, from Kettering University, Flint, Usa, highlighted a result disagreeing with the common sense. The highest ball speed isn’t registered when you have a quick swing and a light bat, neither when the bat is extremely heavy, because the rotation speed would drastically decrease, but there’s a window where increasing the weight cause a light decrease in swing speed bumping up, as a consequence, the ball speed exiting from the face.
This elements influenced the style of players, forced to adapt to new possibilities and situations. But this will be the argument of the next part of our dossier.