Typically speaking, hard courts are “faster” than clay courts. This means the ball will slide more and stay lower when it impacts the court, rather than biting into it and bouncing up such as it does on clay, and therefore reach the opponent more quickly. However, in today’s tennis environment, governing bodies are doing their best to slow this surface down in order to facilitate longer rallies and add to the enjoyment in playing as well as the entertainment value of watching top level tennis. They do this by adding sand to the mixture of actual court surface before it is applied to its concrete base. This gives the court more of a sandpaper texture which prevents the ball from sliding as much through the court and giving the player more time to strike.
But as I said before, typically speaking hard courts are faster than clay. So this surface will help the big servers, such as Pete Sampras, and baseliners that like to play the ball hard and flat like Andre Agassi. What this means for most players is that the preparation must be quicker and simpler, taking the racket back early and having your feet in position to hit faster than you would on clay. You must also use your legs. Remember this ball will not bounce up quite as high, so you must utilize your legs in order to get under the ball.
The movement on a hard court is also monumentally different than clay. Unless your name is Kim Clijsters there will be no sliding into shots on this surface. From the baseline you will see a lot of shots that would come back on clay turn into forcing shots or outright winners on the hard court. Conversely, it is easier for net rushers to attack because they will be able to change directions more quickly and cover the net more effectively. So many passing shots that find their way by a net rusher on clay will come back when the surface is more conducive to rapid changes of direction.
Conventional wisdom tells us that serve and volleyers and big baseline bangers have the advantage over the grinders and heavy topspin clay-courters on a hard surface. However that trend is slowly changing as the organizers make the surfaces slower and slower. It is understandable with all the new racket technology and the strength training that players do these days that the game needs to adjust to these changes. After all nobody wants to watch two players hit only serves for five sets. But in the process we are seeing true serve and volleyers become a thing of the past. Where is the happy medium?