Baseball is still pretty much the same game it was at the turn of the 20th century. Soccer, hockey, and basketball have changed little as well, save for the addition of the 24-second clock, and maybe the three-point line in the latter. Football, though, is quite a different game than it was when the American Professional Football Association, later called the National Football League, was formed in 1920.

Most of the rule changes and adjustments were inspired by the so-called rebel leagues that challenged the NFL over the years, including the All-America Football Conference (AAFC), the (fourth) American Football League (AFL), the World Football League (WFL), and the United States Football League (USFL).

AAFC (1946-1949)

The AAFC made only two significant changes to the game, but they are ones that are with us today. The first was the introduction of a side judge on the officiating crew. The second change was to the league schedule.

More games

When the AAFC launched in 1946, the NFL's 10 teams played an 11-game schedule. The AAFC introduced a 14-game schedule allowing each of the eight teams to play the other seven twice, once home and once away. The NFL didn’t go to 14 games until 1961. It went to 16 games in 1978.

AFL (1960-1970- merged with NFL)

Following the AAFC’s example, the AFL did not greatly alter the rules used by the NFL, but it did make a few notable adjustments. 

Two-point conversion

Introduced in college football in 1958, the AFL also used the two-point conversion until it merged with the NFL in 1970. In 1994, the NFL finally adopted the rule.

Again, more games

The AFL also used a scheduling format that had each team playing the others twice for a total of 14 games to the NFL’s then 12.

Names on jersey

Before the AFL started playing, players were identifiable only by their jersey number. The AFL introduced the idea of including names, primarily for the benefit of TV audiences. It was believed fans would be able to better root for players if they could easily attach a name to the jersey number.

WFL

When the WFL was announced in 1973, league founder Gary Davidson noted that the NFL had become stagnant and complacent. While this was part of his overall sales pitch, he wasn’t entirely wrong. To that end, the WFL introduced several rule changes for its inaugural 1974 season, many of which were quickly adopted by the NFL that same year.

More games

The WFL dispensed with meaningless exhibition contests opting instead for a 20-game regular-season slate to the NFL’s, at the time, 14-game schedule. The older league's teams played six exhibition contests.

Overtime

Before 1974, regular-season NFL games that were tied at the end of regulation went into the books that way. The WFL introduced overtime in the form of two seven-and-half-minute periods both played to completion. The NFL quickly installed sudden-death overtime, which the WFL, in turn, went to in 1975.

Missed Field Goals

An unsuccessful field goal attempt that was not returned by the defending team was placed at the line of scrimmage beyond the 20-yard line under the new WFL rules. That was another change the NFL quickly made. 

Goalposts moved to the back of the end zone

In 1927, college football and the NFL moved the goalposts from the goal line to the backline of the end zone. In 1933, for some inexplicable reason, the NFL moved them back up. The WFL moved the goalposts back, yet another move the NFL followed.

Kickoff placement moved back

NFL kickoffs were made from the 40-yard line, before 1974. The WFL moved them back to the 30 to encourage more kickoff returns. The NFL changed it to the 35-yard line in 1974. From 1994 to 2010, the NFL kicked off from the 30. Today it’s back at the 40.

Thursday Night Football

To avoid direct competition with the NFL, the WFL not only started before the older league’s exhibition season began, it also played its games in the middle of the week. Most games were played on Wednesday night with a nationally televised game on Thursday night. In 2006, the NFL started playing games on Thursday night.

Similarly, many small college football conferences went to mid-week games, to avoid competition with the bigger conferences on Saturdays.

USFL

Unlike the WFL, the USFL wasn’t looking to radically change the game. It had two major rule changes later adopted by the NFL, one of which was the two-point conversion. The other was much more controversial, at least at the time.

Instant replay challenge

For what would be its final season, 1985, the USFL allowed head coaches to challenge a referee’s call. If the call stood, the challenging coach’s team forfeited a time-out. The NFL began experimenting with this in 1986 and uses it today almost identical to the way the USFL did.

In a future post, we’ll look at the rules from rebel leagues not adopted by the NFL.