Remember that the goal line separates the end zone from the rest of the playing field. The end zone also has four orange pylons placed at each of its corners, and these pylons are considered part of the end zone, and the goal line. Extending skyward from the front edge of the goal line is an imaginary wall called the “plane” of the goal line. When the ball touches this imaginary wall, it “breaks the plane.” Under the rules of football, the ball only has to break the plane to score a touchdown. Therefore, the runner’s body doesn’t have to get into the end zone to score a touchdown. He can just stick his ball hand out far enough for the ball to cross even a sliver of the goal line or brush against a pylon.
Moreover, the runner’s body doesn’t even have to be inbounds for a touchdown to count. The plane of the goal line is considered to be a line that extends past the outer boundary lines of the field and around the world. This is called the “around the world rule.” As a result, a player can score without physically being in the field of play. For example, if a runner is diving for the end zone and his body is heading out of bounds, he can still score if the ball touches an orange pylon or breaks the plane that’s stretching around the world before he hits the ground. This might seem like a fantastic scenario, but you’d be surprised how often this happens.
Here is a good example of both of these concepts in action:
So, where does forward progress come in? A touchdown is scored once the ball breaks the plane, regardless of where the runner is tackled, or lands. For example, when a runner, or just the ball, breaks the plane, the defenders can push the runner back out of and away from the end zone, but the touchdown still counts. Because these plays can be so close, two officials must be positioned at the goal line once the ball gets within a certain distance of the goal line. These officials are then in a position to determine whether the runner’s forward progress allowed the ball to break the plane. As you can imagine, this kind of touchdown is challenged by coaches quite often. However, since a referee can only reverse a call with indisputable video evidence, getting these calls reversed isn’t guaranteed.