A touchback is a signal that the returner, a player on the special teams, can make just before catching the ball on a kickoff or punt. To signal a touchback, the returner will drop to the ground on one knee. He must be in his own end zone to signal a touchback. On touchbacks, the receiving team will start with the ball on the 20-yard line.
PRO TIP: The returner will only signal a touchback by dropping on a knee in the end zone. This will allow his team to start with the ball on the 20-yard line.