court handball, indoor or outdoor game played by striking a ball against a wall or walls with the palm of the hand. Play may be for singles or doubles (four players) on a court with one, three, or four walls. The court is typically 20 ft (6.1 m) by 34 ft (10.4 m) with a short line, from behind which the ball is served, marked off 16 ft (4.9 m) from, and parallel to, the front wall, which is 16 ft high. Players hit the ball against the front wall before or after it has struck the floor once. The object is to keep the ball out of the opponent's reach but within the bounds of the court. In the three-wall game, the side walls are also in play, in the four-wall version the back wall also. In all versions, rallies are won when opponents cannot return the ball—made of hard black rubber, 17/8 in. (4.76 cm) in diameter—to the front wall on the fly. Points are scored only when the server wins a rally; the serve changes hand when the receiver wins. Twenty-one points wins a game. Special gloves are used to protect the hands. Although the U.S. Handball Association conducts national and regional championships, the sport, once very popular in YMCAs and public parks, has lost much of its constituency, except in some cities, to racquetball, a four-wall game, invented in the 1950s, that has similar rules but employs short-handled rackets and a fast-moving hollow rubber ball.