The basketball court comes in different shapes and sizes. In the National Basketball Association, the court is 94 feet by 50 ft (28.65 m by 15.24 m). Under International Basketball Federation (FIBA) rules[2], the court is slightly smaller, measuring exactly 28 m by 15 m (91'10.4" by 49'2.6"), although national federations are allowed to use smaller courts, as long as they are at least 26 m by 14 m (85'3.6" by 45'11.2"). A high school court is slightly smaller, at 84' by 50' and some elementary schools have courts measuring 74' x 42'. In amateur basketball, court sizes vary widely. The baskets are always 10' (3.05m) above the floor (except possibly in youth competition).
Center circle
The only two players permitted to enter this area prior to the tipoff are the players contesting the jump ball (usually but not always centers). They both have to jump when the referee throws the ball in the air to attempt to push the ball in the hands of a player of their own team.
Three-point line
The three-point line is the line that separates the two-point area from the three-point area; any shot converted beyond this line counts as three points. If the shooting player steps on the line, it is counted as two points only. Any foul made in the act of shooting beyond the three-point line would give the player three free throws if the shot doesn't go in, and one if it does.
The distance to the three-point from the center of the basket varies depending on the level or league, and has changed several times. These are the current distances, with the league or level using each distance:
19.75 feet (6.02 m): NCAA (women), high school
20.5 feet (6.2 m): International, WNBA
20.75 feet (6.32 m): NCAA (men)
22 feet (6.7 m) to 23.75 feet (7.24 m): NBA
The NBA adopted the three-point line at the start of the 1979-80 season. This is of variable distance, ranging from 22 feet (6.7 m) in the corners to 23.75 feet (7.24 m) behind the top of the key. During the 1994–95, 1995–96, and 1996-97 seasons, the NBA attempted to address decreased scoring by shortening the overall distance of the line to a uniform 22 feet (6.7 m) around the basket. It was moved back to its original distance after the 1996-97 season.
In college basketball as well as in most high school associations in the United States, the distance is 19.75 feet. On May 26, 2007, the NCAA playing rules committee agreed to move the three-point line back one foot to 20.75 feet for the men. This rule went into effect for the 2008-2009 season. The three-point line for women (NCAA) remains at 19.75 feet.
The international distance, used in most countries outside the United States and in FIBA competition, is currently 20.5 feet (6.25 m). The same goes for the WNBA.
Perimeter
The perimeter is defined as the areas that are farthest to the basket but outside of the free throw lane and inside the three-point line. Shots converted in this area are called "perimeter shots" or "medium-range shots".
Low post area
The low post is defined as the areas that are closest to the basket but outside of the free throw lane.[4] This area is fundamental in strategy in American basketball (in international basketball, the key is currently trapezoidal, so low post play is not as prominent). Skilled low post players can score many points per game without ever taking a jump shot.
Key
The key or shaded lane refers to frequently painted area beneath the basket; for NBA, it is 16 feet (4.9 m) wide, for the NCAA it is 12 feet (3.7 m) wide; for both instances it is 15 feet (4.6 m) from the backboard. At the top of the rectangle is the free-throw line, behind which players shoot uncontested shots when they're fouled in the act of shooting or any other penalty. A circle is drawn beyond the free-throw line with a 6 feet (1.8 m) radius; this is used for jump ball instances similarly done at the center circle. There are two 6 in hashes, 3 ft from the free throw line. These marks serve no purpose, though NBA Rule 1 (g) requries them to be drawn.
For FIBA tournaments, the key is currently a trapezoid 3.7 meters (12 ft) wide at the free-throw line and 6 meters (19 feet and 6.25 inches) at the end line.
The key is primarily used to prevent players from staying beneath the basket for long periods.
Restricted area arc
The restricted area arc is an arc 4 feet (1.22 m) from the center of the basket, currently used only in the NBA. With some exceptions, defending players can't force offensive fouls in this area.
Other lines
At NBA floors, two lines are drawn at the end lines near the key - the area directly behind the lines designates the spot where teams on the offensive can inbound the ball.
A similar line parallel to the verticals of the three-point line in NBA floors serves with the same purpose; also this line demarcates the farthest extent a coach (aside from the sidelines) can stay. Directly behind this area is the team bench.
On the half-court line at NBA floors there are 2 lines extending outside the playing court designating the place where substitutes wait before they can enter the playing court; directly behind this area are the various off-court officials such as the timekeeper and reserve referee.
Future changes
On April 26, 2008, FIBA announced several major rules changes involving the court markings. These changes will take effect for major international competitions on October 1, 2010, after that year's World Championships for men and women, and become mandatory for other competitions on October 1, 2012 (although national federations can adopt the new markings before 2012). The changes will be:[5]
* The shape of the key will change from a trapezoid to a rectangle as it is in the NBA, with NBA dimensions.
* The three-point line will move back to 6.75 metres (22 ft 1.7 in) from the current 6.25 metres (20 ft 6.1 in), compared to 23 ft 9 in (7.24 m) for the NBA at the top of the arc.
* FIBA will adopt the NBA's restricted area arc with a marginally wider radius of 1.25 metres (4 ft 1.2 in).
Source: Wikipedia