This rule has a lot more detail I will go into than just what is suggested in the title. It is referring to obstruction without the ball. You can be called for obstruction if you are within three feet of the opposition, did you know that?
Its true, Rule 19.4 states...
19-4 A player will be penalised for obstructing an opposing player that is not in possession of the ball if they are within the 0.9m distance of that player and they employ any movements which take their arms away from their body. Within this distance a player is not obstructing if their arms are outstretched to:
a) Catch, deflect or intercept a pass or feint pass.
b) Obtain a rebound from an unsuccessful shot at goal.
c) Momentarily signal for a pass or to indicate their intended direction of movement.
So, as in this picture, the ball hasn't appeared to rebound yet, the player with her hands in the air is actually obstructing the player that is in front of her.
You can extend that concept to everywhere on the court. A common scenario would be If you are a centre player at the top of the circle defending another centre player. An attack receives the ball under the hoop and is looking to pass out to their centre. You outstretch your hand to attempt to prevent a pass, which is actually obstruction until a pass has actually been made.
Another classic example is when two players are jostling under the hoop. One player is trying to box out another player and they lift their arms away from their sides, they are actually obstructing the opposition.
If you have any questions or feedback regarding this concept please don't hesitate to comment on this blog. The more informed you are the more fun the games will be!