Rebound Ace is also slower but its speed is rather temperature dependent. During the AO, commentators have expressed the fact that because the night temperature is lower, balls tends to be faster because rubber is harder as temperature lowers. So HC players may perform a little better during night matches. Also, ball bounces on rubber court tends to be a little higher due to the elasticity of the material, and its bounce also affected by temperature. During this year's AO match between Mauresmo and Vaidasova, Brad Gilbert suggested this spin theory where Momo often hits high bouncing top-spin shots to throw off Nicole. Whereas hard court and carpet are faster, however, playing hard court is very hard on the body as there is no cushioning on foot landing. If you look at clay, grass, carpet, and rubber, they all provide at least some degree of cushioning.