The International Tennis Federation (ITF) publishes the rules that define what makes a serve good and what makes a serve a fault. Players begin with a first serve. If the first serve results in a fault, the player is entitled to a second serve. If the second serve is also a fault, the player loses a point. This is called "double faulting."
Foot Faults
The ITF rules state that a foot fault occurs when players walk or run during their service motions. In addition, a player can not allow his feet to touch the baseline or center mark, or to cross into the area beyond the sideline. The sidelines and center mark do not end at the baseline; the ITF specifies that players who touch the imaginary extension of either line are still committing foot faults. "The Code," a United States Tennis Association document outlining the code of conduct expected of tennis players, defines flagrant and repeated foot faults as a form of cheating. When no one is officiating a match, a player can warn her opponent for foot faulting.
Service Boxes
When serving, the ball must land in the correct service box. If it lands out of bounds, it is a fault. A ball that touches any part of the line is good. A player begins on the right, or deuce, side of the court and serves diagonally into her opponent's deuce service box. When serving the next game, the player serves from the left, or ad, side of the court and hits the ball diagonally into her opponent's ad service box. The servers then alternate sides for each game. Failure to follow the correct serving pattern results in a fault.
Touching the Ball
According to the official rules of tennis, if a player serves and the ball touches a net post, singles stick or other permanent fixture prior to hitting the ground, it is a fault. In addition, a serve is a fault if the ball touches a player's body or any part of her clothing once the service motion begins. This rule extends to the server's playing partner for doubles matches. The ball cannot touch the partner or the partner's clothing without being called a fault. It is also a fault if a player fails to hit the ball while serving; the ball must at least touch the racket.
References
- International Tennis Federation: Rules of Tennis 2010 (.pdf)
- "Game/Set/Match: A Tennis Guide"; James E. Bryant, James S. Bryant; 2007



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