While much has been made of the new NFL rule regarding initiating contact with the crown of the helmet, it’s a little more specific than that.

In fact, when the NFL put together a video explaining the new rule to players around the league they had trouble finding clips of the situation last season, according to four NFL officials who visited the Lions over the weekend and explained the rule to the players and the media.

Three steps are involved and all must happen outside of the tackle box. The player must line up his target, lower his head and then cause a forcible blow with the crown on his helmet. All three elements must be there for the 15-yard penalty to be called.

Another rule change will force officials to blow a whistle at the end of every play. 

They haven’t done that in the past and said they will have to get into the habit.

“That has been something that there has been feedback from the players. You would hear some whistles, but there would be a lot of times you wouldn’t really get a whistle,’’ coach Jim Schwartz said. “You get something where you hit somebody late and they always say play till the whistle, but there’s no whistle. Our guys are responsible for what they do on the field. They have to be able to judge things.  Particularly around the sidelines, if a guy is out of bounds or not.

“I think that will go a long way to help in some of the situations that have gone where you have had hits. They’re trying to do a lot with player safety with guys in piles and with guys piling into piles. The whistle will help in those cases, too,’’ Schwartz added.

Also players will be required to wear knee and thigh pads. They will be checked prior to the games.

Schwartz doesn’t see this as a big deal at all.

“Our players wear full pads for practices. That’s something that they do for all the four years that I’ve been here,’’ Schwartz said. “It’s not that much of a difference. The technology with pads has increased so much. Anything that they can do to prevent a thigh bruise or a banged knee that maybe puts them out of a practice or miss a game with, I think we’re all in favor of that. Players, coaches, league, everybody.”

Also the tuck rule has been abolished.

And then there’s the Jim Schwartz rule. Now all scoring plays will be reviewed even if the coach throws a challenge flag. You might remember that this cost the Lions big-time in the Thanksgiving loss to Houston.

(Follow @PaulaPasche on Twitter. Order her book,  “100 Things Lions Fans Should Know & Do Before They Die’’ here. It’s also available at bookstores.)