In the sport of cricket, throwing, commonly referred to as chucking, is an illegal bowling action which occurs when a bowler straightens the bowling arm when delivering the ball. The laws of cricket specify that a bowler's arm must not extend during the bowling action. Only the rotation of the shoulder can be used to impart velocity to the ball. Throws are not allowed. If the umpire deems that the ball has been thrown, he will call a no ball which means the batsman cannot be given out from that delivery.