ENGLEWOOD, Colo. – Last year's rule changes and emphasis on hits to the head were initially panned and opposed when they were announced, particularly by defensive players.

But eventually, the opposition faded and players adapted. By the end of the season, it felt like the changes were years old.

Behind the scenes of that smooth transition were the referees that made the rounds with teams during training camp, illustrating and explaining everything the players needed to know. This year, referee crews are doing the same, as one group did Thursday at Dove Valley.

A full version of the video that is shown to players, detailing all of the changes, can be seen above.

For all the worry about the emphasis of illegal contact and defensive holding, the referees don't expect it to be difficult for players to accept the new system.

"When we did this five years ago with the holds," referee Scott Helverson said, "after the four preseason games and Week 1 or 2, it all took care of itself and it all went away. So it can be taught and if we get on it early, they'll adapt."

Helverson was referring to a similar emphasis placed on the rule that didn't take long to feel ingrained into the NFL playing style. He said that even though that emphasis this year may be the toughest for the officials to adapt to as well, it should happen relatively quickly.

"If we can get it going early in preseason and training camp, warn these guys and show them these videos, it'll take care of itself," he said.

Umpire Rich Hall pointed out that in addition to making the presenation to players, officials are talking with them on the sidelines at practice and working with the team's coaches. With position coaches knowing how the new rules are supposed to be called, they can teach their players the proper techniques to avoid drawing flags on the field.

For what the officials saw today on the field, Broncos players haven't been pushing the boundaries.

"I didn't see too much of anything today as far as the illegal contact or the defensive holding or the offensive pass interference," head line judge Wayne Mackie said. "The players were talking about it on the sideline, saying, 'You guys are going to call this?' And we stressed that it's a point of emphasis."

"They will adapt. I don't think it will be a big issue."