From his birch-paneled office in the Laboratory of Physiological Hygiene, under the university's football stadium in Minneapolis ( `` We get a rumble on every touchdown '' ), blocky, grey-haired Dr. Keys directs an ambitious, $200,000-a-year experiment on diet, which spans three continents and seven nations and is still growing.

Starting with the third overtime, a one point PAT field goal after a touchdown is no longer allowed, forcing teams to attempt a two-point conversion after a touchdown.

** if a player is penalized for unsportsmanlike conduct for actions that occurred during a play ending in a touchdown by that team, but before the goal line was crossed, the touchdown will be nullified.

This also applies when the defence scores on a turnover which is returned for a touchdown — technically, they become the offence until the conclusion of the play, and the scoring team must still kickoff.

For example, a point-of-foul infraction committed by the defence in their end zone is not ruled a touchdown, but instead advances the ball to the one-yard line with an automatic first down.

A touchdown in Canadian football is often referred to as a " major score " or simply a " major.

If the team scores a touchdown, starting with the 2010 season, it is required to attempt a 2-point conversion.

The difference between rugby and gridiron-based codes is that in rugby, the ball must be touched to the ground in the in-goal area to count as a try ( the rugby equivalent of a touchdown ), whereas in the gridiron-based games, simply possessing the ball while it is in the end zone is sufficient to count it as a touchdown.

The National Football League changed its rule in 2007, so that a ball carrier merely touching the pylon is insufficient to score a touchdown ; the ball must actually enter the end zone.

It is the line that must be crossed in order to score a touchdown

If any part of the ball reaches any part of the imaginary vertical plane transected by this line while in-bounds and in possession of a player whose team is striving toward that end of the field, this is considered a touchdown and scores six points for the team whose player has advanced the ball to, or recovered the ball in, this position.

If, during the course of play, a loose ball travels past the goal line and is recovered within the end zone, then it is a touchdown if recovered by the team striving toward that goal, or a touchback if recovered and downed by the team striving toward the goal at the opposite end of the field.

The touchdown was controversial because many felt that Pearson pushed off on Vikings defensive back Nate Wright, which is pass interference and a violation of the rules.

It is always played whenever the team scores a touchdown, enters half-time, and at the end of regulation.

During home games at the Metrodome, the Vikings Gjallarhorn is loudly played and sounds often after the team has made a big play, gets a first down, or scores a touchdown.

" The game is remembered by Saints fans for Steve Gleason's blocked punt on the opening series that resulted in a touchdown for New Orleans.

Things got heated in 2011 during a game when Roman Harper illegally hit Panthers wide receiver Steve Smith after Smith scored a touchdown.

Late in the game, a blocked field-goal was reversed by a penalty and Dallas scored the winning touchdown two plays later.

; Conversion ( or Convert ): After a touchdown, the team that scored attempts one scrimmage play from any point between the hash marks on or outside the opponents ' 5-yard line.

Prior to this, the goal line and end line were the same, and players scored a touchdown by leaving the field of play through that line.

In addition, a two-point conversion may be scored after a touchdown by similar means.

The first touchdown in the new facility was scored by Joe Senser on an 11 yard pass from Tommy Kramer.

Rickey Young scored the first regular-season touchdown in the facility on a 3 yard run in the 2nd quarter.

Ahmad Bradshaw scored the game winning touchdown by falling into the end zone.

The Chargers would retake the lead on a field goal by Kaeding then scored again on an 83-yard touchdown run by Michael Turner.

Two plays later, Bears fullback Matt Suhey scored on an 11-yard touchdown run to increase the lead 13-3.

The Patriots finally scored a touchdown early in the fourth quarter, advancing the ball 76 yards in 12 plays and scoring on an 8-yard fourth down pass from Grogan to receiver Irving Fryar.

One irony in the Bears victory was that Payton had a relatively poor performance running the ball and never scored a touchdown in Super Bowl XX, his first and only Super Bowl appearance during his Hall of Fame career ( Many people including Mike Ditka have claimed that the reason for this due to the fact that the Patriots defensive scheme was centered around stopping Walter Payton ).

Taylor caught the ball at the Minnesota 41-yard line, broke Earsell Mackbee's tackle, raced down the sideline, broke through Vikings ' safety Karl Kassulke's tackle and scored the clinching touchdown.

Two plays later, Nowatzke scored on a 2-yard touchdown run and O ' Brien's extra point was good to tie the game, 13 – 13.

Later in the period, Dallas drove 76 yards in nine plays, including a 21-yard reception by Alworth and Calvin Hill's three carries for 25 yards, and then scored on a 7-yard touchdown pass from Staubach to Alworth to increase their lead, 10 – 0.

After 3 running plays, Stabler completed a 17-yard pass to Fred Biletnikoff at the 1-yard line, and running back Pete Banaszak scored a touchdown on the next play, increasing Oakland's lead to 16 – 0 after Mann missed the extra point attempt.

5 plays after the turnover, Dorsett scored on a 3-yard touchdown run.

But later in the period, the Cowboys scored another touchdown on a 45-yard pass from Staubach to receiver Butch Johnson, who made a fingertip catch as he fell into the end zone.

Two plays later on fourth down, Jim Jenson's 16-yard run moved the ball to the 1-yard line, and then Rob Lytle scored on a 1-yard touchdown run to cut the deficit to 20-10.

On the next play, the Cowboys scored on a 29-yard halfback option play: Staubach pitched the ball to fullback Robert Newhouse, who ran left as if it were a normal run play, but then Newhouse passed the ball to Cowboys receiver Golden Richards for a touchdown.

Hill beat Donnie Shell in single-coverage and scored the only first quarter touchdown surrendered by Pittsburgh all season ( In Super Bowl X, the Cowboys also scored a first quarter touchdown against a Steeler team that hadn't permitted one all year ).

The Raiders later scored another touchdown with about a minute left in the quarter.

But it was overruled by instant replay: the officials ruled that Monk's foot was out of bounds when he caught the ball ( the first time a touchdown was overruled by instant replay in a Super Bowl ).

They also had a defense fumble return touchdown overturned by instant replay.

A team scores a touchdown by entering its opponent's end zone while carrying the ball or catching the ball while being within the end zone.

The punter, with an impromptu dash to his right, tossed the ball and it was caught by George Stephens, who ran 70 yards for a touchdown.

Timekeeper Walter McCormack walked onto the field to end the game when the ball was thrown twenty-five yards and caught on the dead run for a touchdown.

In the 1982 Big Game between Stanford and California, with four seconds left and trailing by one point, Cal ran the ball back on a kickoff all the way for the game-winning touchdown using five backward passes, eventually running through the Stanford Band, who had already taken the field ( believing the game was over after Stanford players appeared to have tackled a Cal ball-carrier ).

With time winding down the Saints threw backward passes and brought the ball down the length of the field for a touchdown, but kicker John Carney missed the extra point, which would have tied the game, so the Saints lost by one point, 20 – 19.

After a Giants three-and-outs, Matt Dodge punted the ball to Desean Jackson, who returned it for a touchdown, concluding the Giants ' epic collapse.

The Patriots were allowing Bradshaw to get the touchdown so they would get the ball with some time remaining.

He batted and kicked the ball into the end zone, where he fell on it for the game-tying touchdown as time ran out.

What many Charger fans believed should have been called an incomplete pass ( and possibly intentional grounding ) was seen as a fumble and the rest of the play involved batting of the ball forward towards the end zone where the Raiders ultimately recovered it for a touchdown.

The ball bounced off Hinton's hands, was tipped by Dallas defensive back Mel Renfro, and finally ended up in the arms of tight end John Mackey, who took the ball 75 yards for a touchdown, tying the score 6 – 6 after Jim O ' Brien's extra point attempt was blocked.