In a press conference at the Monte Carlo Masters, Gilles Simon explained why Rafael Nadal struggles more on hard courts physically and Roger Federer struggles more on clay. The Spaniard just played a few events on the surface in the last year and a half, and the Swiss is set to make his comeback on the dirt in the next month's Madrid Open.
The Frenchman said: "The big problem on a hard surface is that it's not the same kind of hard surface as before when there were some surfaces that were really, really fast. For instance, in the United States, we are playing on sand that sticks, and the knees could be easily injured.
I remember that when I played over there. They are very slow, and they bounce very high. They could be really aggressive, and you have all the sorts of hard surfaces that are really fast, and the courts are a little bit more worn out and are a little bit more slippery, and the rallies are shorter and we are not hurt.
And on clay normally the knees do not suffer. What is really bad is when you take a good stance and then your knees have to absorb the shock, and on clay that is fine. When you are on hard surface, sometimes you feel this sort of wave going through your knees all the way up to your hips, and it is true that on clay, on the other hand, when you have to turn around, it's a little bit more complicated, like in the case of Roger that he maybe has the same spine as mine.
So probably as Roger, I also have the same pain in the back. Probably this explains why, for him, clay is more dangerous or aggressive for him than for Rafa. And when Rafa slides on clay, that's all right, but he cannot do the same on a hard surface."