What's that on the basketball court?

[mikeargo]

I gave up watching NBA basketball after Larry and Magic retired, but I have been watching this year’s playoffs. I noticed that there is now a semi-circle marked on the court inside the “key” area. What’s up with that?

[borschevsky]

I think that’s the “no charging” area. If a defender is in that area he can’t draw a charging foul on a player driving to the basket. I am not sure of the exact rule, though. I think the call can depend on several other factors as well (if the player passes or shoots, if he goes to the basket from the middle of the court or from the baseline, etc.).

[Rysdad]

Are you talking about the jump ball area?

[Quercus]

I think he’s talking about the ‘no charge’ line – a four foot circle underneath the basket. Borschevsky got it right.

You want the formal definition?
From www.nba.com

An offensive foul should never be called if the contact is with a secondary defensive player who has established a defensive position within a designated “restricted area” near the basket for the purpose of drawing an offensive foul. The “restricted area” for this purpose is the area bounded by an arc with a 4-foot radius measured from the middle of the basket. EXCEPTION: Any player may be legally positioned within the “restricted area” if the offensive player receives the ball within the Lower Defensive Box.

Clear as mud, eh? Don’t ask what a ‘secondary defensive player’ is, or even what the ‘Lower Defensive Box’ is, because I can’t seem to find them defined in the rules section. Note that the above quote comes NOT from the Rules section (which never mentions the no charge line) but from the Basic Principles section (comments and clarifications, essentially.) Nothing like a clarification that adds a whole new rule.

I always thought NBA rules were defined mostly in the referee’s heads (like the ‘Jordan rule’ that changes the definition of a foul depending on how big an endorsement contract the player has), but after looking at the official rules on-line, I’m sure of it. Yeesh.

[Mullinator]

The main purpose of this rule is to limit injuries. Imagine a really big person flying through the air while another big person steps into the path trying to take a charge. The combo of the airborne person being undercut by the person taking a charge and then having both land in the most highly trafficed area of a court has a prety good chance of resulting in an injury. Being undercut is not a fun feeling, even less so when it’s likely you will also be stepped on by another player after landing. My experience has been that it doesn’t feel too good.

A secondary defensive player is a defender that is coming over to help out on defense on a player he wasn’t initally guarding.

The lower defensive box is basically the section of the floor that is closer to the basket than the mid range to 3 point areas.