<P> A basketball (basketball ball) is a spherical ball used in basketball games . Basketballs typically range in size from very small promotional items only a few inches in diameter to extra large balls nearly a foot in diameter used in training exercises . For example, a youth basketball could be 27 inches (69 cm) in circumference, while an National Collegiate Athletic Association (NCAA) men's ball would be a maximum of 30 inches (76 cm) and an NCAA women's ball would be a maximum of 29 inches (74 cm). The standard for a basketball in the National Basketball Association (NBA) is 29.5 inches (75 cm) in circumference and for the Women's National Basketball Association (WNBA), a maximum circumference of 29 inches (74 cm). High school and junior leagues normally use NCAA, NBA or WNBA sized balls . </P> <P> Aside from the court and the baskets, the basketball is the only piece of equipment necessary to play the game of basketball . During the game, the ball must be bounced continuously (dribbling), thrown through the air to other players (passing) and towards the basket (shooting). Therefore, the ball must be very durable and easy to hold on to . The ball is also used to perform tricks (sometimes called freestyling), the most common of which are spinning the ball on the tip of one's middle finger, dribbling in complex patterns, rolling the ball over one's shoulder, or performing aerobatic maneuvers with the ball while executing a slam dunk, most notably in the context of a slam dunk contest . </P>

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