Once the play begins, it will continue until one of the following events happens: * The ball carrier is down, usually defined as when any body part besides the hands and feet touches the ground. * The ball carrier's forward progress is stopped to the point where a stalemate occurs and it is clear that the ball cannot be advanced any farther, nor is he easily going down as defined above. * The ball carrier steps out of bounds. * A forward pass touches the ground before it is caught (an incomplete pass). The ball touching the ground in other situations (called a fumble) does NOT end the play. In the case of a fumble, the play still continues until one of the above conditions is met.