Rules and Regulation

Measurements and time limits discussed in this section often vary among tournaments and organizations; international and NBA rules are used in this section.

The object of the game is to outscore one's opponents by throwing the ball through the opponents' basket from above while preventing the opponents from doing so on their own. An attempt to score in this way is called a shot. A successful shot is worth two points, or three points if it is taken from beyond the three-point arc which is 6.25 metres (20 ft 6 in) from the basket in international games and 23 feet 9 inches (7.24 m) in NBA games. A one-point shot can be earned when shooting from the foul line after a foul is made.

 

Playing regulations

Games are played in four quarters of 10 (FIBA) or 12 minutes (NBA). College games use two 20-minute halves, while high school varsity games use 8 minute quarters. Fifteen minutes are allowed for a half-time break under FIBA, NBA, and NCAA rules and 10 minutes in high school. Overtime periods are five minutes in length except for high school which is four minutes in length. Teams exchange baskets for the second half. The time allowed is actual playing time; the clock is stopped while the play is not active. Therefore, games generally take much longer to complete than the allotted game time, typically about two hours.
Five players from each team may be on the court at one time. Substitutions are unlimited but can only be done when play is stopped. Teams also have a coach, who oversees the development and strategies of the team, and other team personnel such as assistant coaches, managers, statisticians, doctors and trainers.
For both men's and women's teams, a standard uniform consists of a pair of shorts and a jersey with a clearly visible number, unique within the team, printed on both the front and back. Players wear high-top sneakers that provide extra ankle support. Typically, team names, players' names and, outside of North America, sponsors are printed on the uniforms.
A limited number of time-outs, clock stoppages requested by a coach (or sometimes mandated in the NBA) for a short meeting with the players, are allowed. They generally last no longer than one minute (100 seconds in the NBA) unless, for televised games, a commercial break is needed.
The game is controlled by the officials consisting of the referee (referred to as crew chief in the NBA), one or two umpires (referred to as referees in the NBA) and the table officials. For college, the NBA, and many high schools, there are a total of three referees on the court. The table officials are responsible for keeping track of each teams scoring, timekeeping, individual and team fouls, player substitutions, team possession arrow, and the shot clock.

 

Equipment

Traditional eight-panel baske

The only essential equipment in a basketball game is the basketball and the court: a flat, rectangular surface with baskets at opposite ends (or in the case of 3-on-3 street basketball, half a court with one basket). Competitive levels require the use of more equipment such as clocks, scoresheets, scoreboard(s), alternating possession arrows, and whistle-operated stop-clock systems.

An outdoor basketball net.

A regulation basketball court in international games is 28 metres (91.9 ft) long and 15 metres (49.2 ft) wide. In the NBA and NCAA the court is 94 feet (28.7 m) by 50 feet (15.2 m). Most courts have wood flooring, usually constructed from maple planks running in the same direction as the longer court dimension. The name and logo of the home team is usually painted on or around the center circle.
The basket is a steel rim 18 inches (45.7 cm) in diameter with an attached net affixed to a backboard that measures 6 feet (182.9 cm) by 3.5 feet (106.7 cm), and one basket is at each end of the court. The white outlined box on the backboard is 18 inches (45.7 cm) high and 2 feet (61.0 cm) wide. At almost all levels of competition, the top of the rim is exactly 10 feet (305 cm) above the court and 4 feet (121.9 cm) inside the baseline. While variation is possible in the dimensions of the court and backboard, it is considered important for the basket to be of the correct height - a rim that is off by just a few inches can have an adverse effect on shooting.
The size of the basketball is also regulated. For men, the official ball is 29.5 inches (74.9 cm) in circumference (size 7, or a "295 ball") and weighs 22 ounces (624 g). If women are playing, the official basketball size is 28.5 inches (72.4 cm) in circumference (size 6, or a "285 ball") with a weight of 20 ounces (567 g).

 

Violations

The ball may be advanced toward the basket by being shot, passed between players, thrown, tapped, rolled or dribbled (bouncing the ball while running).
The ball must stay within the court; the last team to touch the ball before it travels out of bounds forfeits possession. The ball is out of bounds if touches or crosses over a boundary line, or touches a player who is out of bounds. This is in contrast to other sports such as football, volleyball, and tennis (but not rugby or American football) where the ball (or player) is still considered in if any part of it is touching a boundary line.
The ball-handler may not move both feet without dribbling, an infraction known as traveling, nor may he dribble with both hands or catch the ball in between dribbles, a violation called double dribbling. A player's hand cannot be under the ball while dribbling; doing so is known as carrying the ball. A team, once having established ball control in the front half of the court, may not return the ball to the backcourt and be the first to touch it. The ball may not be kicked, nor be struck with the fist. A violation of these rules results in loss of possession, or, if committed by the defense, a reset of the shot clock (with some exceptions in the NBA).
There are limits imposed on the time taken before progressing the ball past halfway (8 seconds in international and NBA; 10 seconds in NCAA men's play and high school for both sexes, but no limit in NCAA women's play), before attempting a shot (24 seconds in the NBA, 30 seconds in NCAA women's and Canadian Interuniversity Sport play for both sexes, and 35 seconds in NCAA men's play), holding the ball while closely guarded (5 seconds), and remaining in the restricted area below the foul line (the lane, or "key") (3 seconds). These rules are designed to promote more offense.
No player may touch the ball on its downward flight to the basket, unless the ball has no chance of entering the basket (goaltending). In addition, no player may touch the ball while it is on or in the basket; when any part of the ball is in the cylinder above the basket (the area extended upwards from the basket); or when the ball is outside the cylinder, if the player reaches through the basket and touches it. This violation is known as "basket interference". If a defensive player goaltends or commits basket interference, the basket is awarded and the offending team gets the ball. If a teammate of the shooter goaltends or commits interference, the basket is cancelled and play continues with the defensive team being given possession.

 

Fouls

An attempt to unfairly disadvantage an opponent through physical contact is illegal and is called a foul. These are most commonly committed by defensive players; however, they can be committed by offensive players as well. Players who are fouled either receive the ball to pass inbounds again, or receive one or more free throws if they are fouled in the act of shooting, depending on whether the shot was successful. One point is awarded for making a free throw, which is attempted from a line 15 feet (4.6 m) from the basket.

The referee signals that a foul has been committed.

The referee may use discretion in calling fouls (for example, by considering whether an unfair advantage was gained), sometimes making fouls controversial calls or no-calls. The calling of fouls can vary between games, leagues and even among referees.
A player or coach who shows poor sportsmanship, such as by arguing with a referee or by fighting with another player, can be charged with a more serious foul called a technical foul. The penalty involves free throws (where, unlike a personal foul, the other team can choose any player to shoot) and varies among leagues. Repeated incidents can result in disqualification. Blatant fouls with excessive contact or that are not an attempt to play the ball are called intentional fouls (or flagrant fouls in the NBA). In FIBA, a foul resulting in ejection is called a disqualifying foul, while in leagues other than the NBA, such a foul is referred to as flagrant.
If a team exceeds a certain limit of team fouls in a given period (quarter or half) – four for NBA and international games – the opposing team is awarded one or two free throws on all subsequent non-shooting fouls for that period, the number depending on the league. In the US college and high school games, if a team reaches 7 fouls in a half, the opposing team is awarded one free throw, along with a second shot if the first is made. This is called shooting "one-and-one". If a team exceeds 10 fouls in the half, the opposing team is awarded two free throws on all subsequent fouls for the half.
When a team shoots foul shots, the opponents may not interfere with the shooter, nor may they try to regain possession until the last or potentially last free throw is in the air.
After a team has committed a specified number of fouls, it is said to be "in the penalty". On scoreboards, this is usually signified with an indicator light reading "Bonus" or "Penalty" with an illuminated directional arrow indicating that team is to receive free throws when fouled by the opposing team. (Some scoreboards also indicate the number of fouls committed.)
If a team misses the first shot of a two-shot situation, the opposing team must wait for the completion of the second shot before attempting to reclaim possession of the ball and continuing play.
If a player is fouled while attempting a shot and the shot is unsuccessful, the player is awarded a number of free throws equal to the value of the attempted shot. A player fouled while attempting a regular two-point shot, then, receives two shots. A player fouled while attempting a three-point shot, on the other hand, receives three shots.
If a player is fouled while attempting a shot and the shot is successful, typically the player will be awarded one additional free throw for one point. In combination with a regular shot, this is called a "three-point play" or "four-point play" (or more colloquially, an "and one") because of the basket made at the time of the foul (2 or 3 points) and the additional free throw (1 point).

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