In basketball, the referees are responsible for calling all fouls and violations on players that break the rules of the game. One of the most controversial and highly debated calls in basketball is the difference between charging and blocking fouls.
A blocking foul is an illegal act that will be called on a defensive player who does not get into position in time prior to the dribbler moving in that direction. The referee will use the dribbler's speed to determine how much space on the court the defensive player needed to make prior to setting up the screen. Most contact with the body on an offensive player is referred to as a blocking foul.
A charge is called on the dribbler if he collides with a defensive player who has established legal position on his way to the basket. Legal position entails feet set and the torso in between the offensive player and the basket. The defending player can not be in the act of shuffling into this position, as they must be set prior to the contact. This is the hardest real-time differentiation for referees to see when making the call.
Defensive players will often flop to draw and draw a charge call, meaning they will over exaggerate the amount of contact they received and will fall to the ground to make the offensive player look guilty of the foul.
The restricted area in a component of the court that defensive players are not allowed to stand in when taking a charge. If a player's feet are on the line then it is automatically considered a blocking foul.