All the NFL rule changes you need to be aware of ahead of the new season

A new NFL season is set to begin with last year's experiment on the new kickoff becoming permanent with a new tweak and several other changes in rules and officiating.

The league also will implement changes to the overtime rule for the regular season, expand replay assist, crack down on bad sportsmanship and use Hawk-Eye virtual measuring to replace the old-time chains to determine first downs.

The league experimented with the so-called dynamic kickoff in 2024 in hopes of more returns while also making the play safer. Owners voted in April to make the change permanent while moving touchbacks on kicks that reach the end zone on the fly from the 30 to the 35, which is expected to lead to more kicks in play and more returns.

There was no change in the tush push play that Philadelphia used so successfully on the way to winning the Super Bowl last season.

The league was mostly pleased with the experimental kickoff put in place for 2024 that led to the rate of kickoff returns increasing from a record-low 21.8 per cent in 2023 to 32.8 per cent last season, while reducing the rate of injuries on what had been the game's most dangerous play.

The rule made kickoffs more like scrimmage plays by placing the coverage players and blockers close together to eliminate the high-speed collisions that had contributed to so many injuries on the play. The league said the rate of concussions dropped 43 per cent on returns, with a significant reduction as well in lower-body injuries.

The problem last season was many teams still opted to kick the ball in the end zone because the touchback wasn't punitive enough. The average starting field position on a touchback was only 2.4 yards further than the average starting position after returns, which was the 27.6-yard line.

By moving the touchback to the 35, the league projects that the return rate will rise to somewhere between 60 per cent and 70 per cent, with a similar increase in long returns, adding more excitement to the game.

Teams returned just over 76 per cent of kicks in the preseason, up from 70 per cent in the 2024 preseason. But that number typically drops in the regular season when teams don't use kickoffs to evaluate players for spots at the end of the roster.

The league approved a proposal to make the regular season overtime more like the postseason, with both teams getting a chance at a possession, even if the team that gets the ball first scores a touchdown.

The NFL expanded its replay assist system to overturn objective calls if there was 'clear and obvious' evidence that a foul didn't occur.

The calls could include facemask penalties, whether there was forcible contact to the head or neck area, horse-collar tackles and tripping. Replay also would be able to overturn a roughing-the-kicker or running-into-the-kicker penalty if video showed the defender made contact with the ball.

Referees will no longer use the chains to determine first downs, opting instead for a virtual measuring system. This won't eliminate the officials who manually spot the ball and use chains to mark the line to gain.

The Hawk-Eye system consists of six 8K cameras for optical tracking of the position of the ball with the result shown on stadium scoreboards.

The league estimates that measurements will take about 30 seconds - about 40 seconds fewer than the average with the chains - although it took longer at times in the preseason.

The league is also emphasizing sportsmanship and cracking down on violent and sexually suggestive gestures this season.

In April, the NFL expanded prohibited acts to include banning the 'nose wipe' gesture that league executive Troy Vincent said is affiliated with gangs.

The unsportsmanlike conduct rule now states: 'any violent gesture, which shall include but not be limited to a throat slash, simulating firing or brandishing a gun, or using the `nose wipe´ gesture, or an act that is sexually suggestive or offensive.'