The boundaries of a basketball court are used to determine if the ball or a player goes out of bounds. There are rules associated with being out of bounds as a player. When the ball goes out of bounds, a throw-in and sometimes a jump ball is used to put the ball back into play.
The sidelines and baselines make up the boundary lines on a basketball court. A player is out-of-bounds if they step on or cross the boundary lines with their feet or touch any object that is out of play.
The rules of out-of-bounds and the boundary lines in basketball can be confusing, here are the key things you need to know:
Throw-ins, also known as inbound passes, are used to put the ball into play after the ball goes out of bounds. The referee will award the ball to the team that gets possession at the nearest sideline spot. On a throw-in, the thrower stands out of bounds and passes the ball to a teammate who is inbounds. They must keep both feet planted until the ball is released from their hands. A defender usually tries to block inbound passes. Teams will generally assign someone very tall to guard inbounds passes as it makes it difficult to pass the player with the ball.
Whenever the referees cannot figure out which team caused the ball to go out-of-bounds, a jump ball will be used to put the ball into play. This is only when video review proves inconclusive and jump balls are usually a last resort. Teams will usually let their tallest player take the jump ball. For a jump ball, a referee throws the ball in the air and two players jump and try to deflect it towards their teammates. Jump balls are considered a fair way to decide which team gets possession. Jump balls also occur at the beginning of games.
In basketball, a ball is out of bounds if it touches a player who is out of bounds or lands out of bounds on the floor. The ball is also out if it hits any of the objects behind the basket or backboard. When the ball goes out of bounds, whichever team sent it out loses possession. If it is impossible to tell who touched the ball last before it went out of bounds, a jump ball will be called.
An athlete that is out of bounds cannot play the ball, but as soon as both of their feet are back in the court, they can interact with the ball again. So, if a player is run out of bounds, they must return to the court before being able to contribute to the team.