Forward progress can end a play but doesn't always. If you're referring to last night's Texas/Iowa state game, the ruling on the field stood because the replay official decided that the forward progress had stopped even though the runner was still fighting for yards. The officials will give a ball carrier a chance to break a tackle before they blow the whistle, but if it becomes obvious that he can't, forward progress stops the play. That's why you see a ball get moved forward after a player gets knocked backwards before the whistle.
5 months ago
Last edited at 9:55AM on 10/4/2013
The referees will usually let the stoppage of forward progress continue because the runner has a chance to break away from the tacklers, but if it takes long enough, the referee will blow the whistle to stop the play and call it dead. The same rule applies to the National Football League.