Before The Serve, 2010 US Open

Hard courts (usually made of asphalt) are very fast types of tennis courts, where fast hard-hitting players have a slight advantage. Hard courts can vary in speed; they are faster than clay but not as fast as grass courts. Depending on the amount of sand added to the paint the amount the ball slows down can vary greatly. These courts are considered the most equal for all playing styles. The U.S. Open is played on an acrylic hard court, while the Australian Open is played on a synthetic hard court. The main difference between a synthetic hard court and a true hard court surface is the level of hardness. When the ball bounces on this surface it is faster than all other surfaces if there is not much sand in the top paint. The amount of sand used in the top paint and the size of the sand also determines the speed – more sand means less speed and larger sand particles will slow the speed of play. The amount of friction can also be altered and more friction will produce a clay court effect, where topspin is magnified. The extra grip and friction will resist the sliding effect of the ball and the resistance will force the ball to change its rotation. The extra grip provided by the surface can resist the movement of the player and can cause injury.
A serve (or, more formally, a service) in tennis is a shot to start a point. A player begins a serve by tossing the ball into the air and hitting it (usually near the highest point of the toss) into the diagonally opposite service box without being stopped by the net. The ball can only touch the net on a return and will be considered good if it falls on the opposite side. If the ball contacts the net on the serve but then proceeds to the proper service box, it is called a let; this is not a legal serve in the major tours although it is also not a fault. Players typically serve overhead, but serving underhand, although rare, is allowed. The serve is the only shot a player can take their time to set up instead of having to react to an opponent's shot.