Tennis is a racket sport that can be played individually against a single opponent (singles) or between two teams of two players each (doubles). Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent's court. The object of the game is to maneuver the ball in such a way that the opponent is not able to play a valid return. The player who is unable to return the ball will not gain a point, while the opposite player will.|
The rules of modern tennis have changed little since the 1890s. Two exceptions are that from 1908 to 1961 the server had to keep one foot on the ground at all times, and the adoption of the tiebreak in the 1970s. A recent addition to professional tennis has been the adoption of electronic review technology coupled with a point-challenge system, which allows a player to contest the line call of a point, a system known as Hawk-Eye.
The invention of the first lawn mower in 1830, in Britain, is believed to have been a catalyst, for the preparation of modern-style grass courts, sporting ovals, playing fields, pitches, greens, etc. This in turn led to the codification of modern rules for many sports, including lawn tennis, most football codes, lawn bowls and others.
On 21 May 1881, the oldest nationwide tennis organization in the world was formed, the United States National Lawn Tennis Association (now the United States Tennis Association) in order to standardize the rules and organize competitions. The U.S. National Men's Singles Championship, now the US Open, was first held in 1881 at the Newport Casino, Newport, Rhode Island. The U.S. National Women's Singles Championships were first held in 1887 in Philadelphia.
The comprehensive rules promulgated in 1924 by the ILTF, have remained largely stable in the ensuing eighty years, the one major change being the addition of the tiebreak system designed by Jimmy Van Alen. That same year, tennis withdrew from the Olympics after the 1924 Games but returned 60 years later as a 21-and-under demonstration event in 1984. This reinstatement was credited by the efforts by the then ITF President Philippe Chatrier, ITF General Secretary David Gray and ITF Vice President Pablo Llorens, and support from IOC President Juan Antonio Samaranch. The success of the event was overwhelming and the IOC decided to reintroduce tennis as a full medal sport at Seoul in 1988.
The components of a tennis racket include a handle, known as the grip, connected to a neck which joins a roughly elliptical frame that holds a matrix of tightly pulled strings. For the first 100 years of the modern game, rackets were made of wood and of standard size, and strings were of animal gut. Laminated wood construction yielded more strength in rackets used through most of the 20th century until first metal and then composites of carbon graphite, ceramics, and lighter metals such as titanium were introduced. These stronger materials enabled the production of oversized rackets that yielded yet more power. Meanwhile, technology led to the use of synthetic strings that match the feel of gut yet with added durability.
Advanced players improve their performance through a number of accoutrements. Vibration dampeners may be interlaced in the proximal part of the string array for improved feel. Racket handles may be customized with absorbent or rubber-like materials to improve the players' grip. Players often use sweat bands on their wrists to keep their hands dry and head bands or bandanas to keep the sweat out of their eyes as well. Finally, although the game can be played in a variety of shoes, specialized tennis shoes have wide, flat soles for stability and a built-up front structure to avoid excess wear.
For a service to be legal, the ball must travel over the net without touching it into the diagonally opposite service box. If the ball hits the net but lands in the service box, this is a let or net service, which is void, and the server retakes that serve. The player can serve any number of let services in a point and they are always treated as voids and not as faults. A fault is a serve that falls long or wide of the service box, or does not clear the net. There is also a "foot fault" when a player's foot touches the baseline or an extension of the center mark before the ball is hit. If the second service, after a fault, is also a fault, the server double faults, and the receiver wins the point. However, if the serve is in, it is considered a legal service.
A game point occurs in tennis whenever the player who is in the lead in the game needs only one more point to win the game. The terminology is extended to sets (set point), matches (match point), and even championships (championship point). For example, if the player who is serving has a score of 40-love, the player has a triple game point (triple set point, etc.) as the player has three consecutive chances to win the game. Game points, set points, and match points are not part of official scoring and are not announced by the chair umpire in tournament play.
Balls wear out quickly in serious play and, therefore, in ATP and WTA tournaments, they are changed after every nine games with the first change occurring after only seven games, because the first set of balls is also used for the pre-match warm-up. As a courtesy to the receiver, the server will often signal to the receiver before the first serve of the game in which new balls are used as a reminder that they are using new balls. However, in ITF tournaments like Fed Cup, the balls are changed in a 9–11 style. Continuity of the balls' condition is considered part of the game, so if a re-warm-up is required after an extended break in play (usually due to rain), then the re-warm-up is done using a separate set of balls, and use of the match balls is resumed only when play resumes.