CONCLUSION: A SNEAK PEEK INTO PART II
The lack on inertia is one of the reasons why some players struggle on clay. However, there are also others, in addition to the purely tactical ones, which mostly concern the mechanics of the shots (especially in terms of the compactness of groundstroke backswings). The behavior of the ball during its trajectory from one surface to another is what in physics is called the “Magnus effect”, but this is another story, that we will tell you in the next article, in which we will outline some hypotheses about the characteristics that are necessary to perform well on clay. Today we leave you with this pretty chart (from the same Twitter handle, our bona fide guardian angel) and a consideration.
It seems correct to suggest that the analysis of the speed of courts should also include the behaviour of topspin shots. It is not enough to infer conclusions on the speed of a court based only on the flat shots that arrive at narrow angles (i.e. the ideal laboratory conditions used to calculate the CPR).
The result obtained by comparing the yield of a flat shot and a topspin one (on clay and hard, respectively) may lead to the same result by comparing different types of wehardcourts. As the above chart shows, it is possible to range from courts – blue area, top left – that are very fast (low coefficient friction values) but with a very generous rebound (high coefficient restitution values) to those – moving to the right side of chart – that tend to be slow (high coefficient friction values) but with a less pronounced bounce (medium restitution coefficient values). Ultimately, it is possible to state that there are hardcourts that slow down flat shots but let topspin strokes travel quite well, a bit like on clay – it could be said that these courts are slow and fast at the same time, and whether they appear fast or slow depends also on who is playing on them. Therefore, it is not uncommon that the opinion of tennis players on a specific surface might result different. One example among many was recorded during the 2013 ATP Finals, when Nadal was convinced that the courts in London were slower than those of Bercy, while according to Djokovic they were faster. In short, trust with moderation and prudence what the players and the CPR say. See you for part II!
Article by Alessandro Stella; translated by Andrea Canella; edited by Tommaso Villa
