Comparison of American football and rugby union

Players who are red carded automatically face a disciplinary hearing, and can be banned for a period of time from one week to permanently depending on the level of offence.

In American football, players are only disqualified for Unsportsmanlike Conduct and related penalties (Fighting, Palpably Unfair Acts, etc.).

Most notably, a rugby union game will continue after the scheduled end of a half (half-time or full-time) until the ball becomes dead - any occurrence that would have play restart with a scrum or lineout, or when a team scores.

This has led to some "nail-biting" finishes where teams losing by only a small margin work their way towards scoring, and games can go on several minutes over time.

In both sports, the clock is also stopped during substitutions and for injuries, so the referee does not need to add stoppage time as is done in soccer/Association football.

In addition to this, the half-time break is typically 12 to 15 minutes; this intermission allows for resetting of strategy in both rugby and American football and adjusting to the opponent's schemes.

In 1876, Yale, Harvard, Princeton, and Columbia formed the Intercollegiate Football Association, a competition based on the traditional rules of rugby.

The schism in English rugby was caused by several economic factors for the northern clubs which made up the majority of the teams.

The popularity of college football grew as it became the dominant version of the sport in the United States for the first half of the twentieth century.

Initially a sport of Midwestern industrial towns in the United States, professional football eventually became a national phenomenon.

The end zone in American football has a fixed depth of 10 yards (9.1 m) whilst in Rugby Union the goal area must be between a minimum depth of 10 metres (11 yd) and a maximum of 22 metres (24 yd) between the goal line and the dead ball line at the rear of the field.

The yard lines of American football are vitally important during game play because a team's advance is measured against them which, in turn, determines possession of the ball.

The 22 metre lines determine the position from which drop-outs are taken and also mark the limit where a defending player may kick-the ball directly (without bouncing) into touch without losing the ground gained by the kick.

Though these technically run across the pitch they can more usefully be regarded as longitudinal lines because each hash mark is only a yard long and they are so numerous that they create more obvious pattern down the field than across it (see below).

American football goalposts were formerly H-shaped and were located on the goal line, but; in 1967, the NFL adopted the current modern offset-fork design, made from extruded steel pipes.

The central vertical post is offset from the crossbar toward the rear, placing it as far as possible from the field of play; it is also usually padded to minimize collision-related injuries.

In American football, it is normal to punt on the last down, but, as in rugby union, a kick can take place at any phase of play.

In high school football, this can also be called if the defense commits repeated and intentional fouls at the goal line.

Also, American football features the option of the going for a 2-point conversion, where the attacking team gets one chance from 3 yards out (2 in the NFL) to get the ball in the end zone again.

Plus, all American football, except high school (all but Texas), allows conversion turnovers that are returned for touchdowns to be given 2 points.

In American football, a field goal is generally kicked from seven yards behind the line of scrimmage, with the "holder" receiving a "long snap" from the center.

Following the award of the penalty, the attacking team may opt to kick for goal rather than advance the ball by hand or punting, or forming a scrum.

A rare play called a "fair catch kick" is analogous to a goal from mark which existed in rugby union at one time.

Moreover, rugby union hits are not usually at the speed of American football both because of the nature of the game and the lack of protective equipment.

In American football, players receiving a forward pass are often extremely vulnerable because they must concentrate on catching the ball, often jumping very high or stretching out and thereby exposing their body to punishing hits; in rugby a player is not allowed to be tackled in the air, leaving the receiver of the kick with more time to assess his surroundings, usually in rugby ball carriers can anticipate a hit and can brace themselves accordingly.

In rugby, rucks and mauls may develop following a tackle when multiple players from each team bind together to move the ball in play (on the ground or in-hand respectively).

The prohibition of metal resulted in one of the most unusual[peacock prose] pieces of protective gear ever seen in any sport in a 2010 Heineken Cup semifinal between Biarritz and Munster.

Biarritz star Imanol Harinordoquy had suffered a broken nose in a domestic encounter with Racing Métro's Sébastien Chabal, and had undergone surgery to repair it.

An unintended consequence of all the safety equipment has resulted in increasing levels of force in the game which, unprotected and in current form, would now be extremely dangerous.

An example of this is the trend for players tackling head first rather than leading with a shoulder, which has led to some serious neck injuries, including breaks, even with the helmets used.