Palm Beach, Fla. ? The NFL’s new emphasis on improving offense will come with a cost: longer games.

The league wrapped up its annual spring meeting Wednesday with several expected moves, including the approval of some new rules and setting out to make sure existing ones are enforced properly.

They include adding a 15-yard penalty for Terrell Owens/Joe Horn type demonstrations, especially when they are orchestrated by groups of players. The penalties will be in addition to fines already in place for such end zone acts as Horn pulling out a cell phone from under the goal post, or Owens taking a pen out of his sock and autographing a ball.

But the greater effect is likely to come from a new emphasis on holding and illegal contact by defensive backs; illegal blocks on kicking plays; and an added replay challenge for teams that are successful on their first two.

That means more penalties, many of them for illegal contact on passing plays after passing yardage was at an 11-year low last season.

“Yes, games will probably get a little longer,” said Rich McKay, co-chairman of the competition committee. “You’re always conscious of the length of games. It’s not something you want to encourage. But we felt we had to do something about passing yardage going down.”

McKay said he thought game times would come down once players made adjustments.

Of far more consequence was the possibility of the new NFL Network televising live games. Commissioner Paul Tagliabue said that could happen in the future, which would give the league a bargaining chip in negotiations with the networks.

Tagliabue said games on the five-month old satellite and cable network weren’t likely in the next contract, on which negotiations are about to begin. The current $17.6 billion, eight-year deal expires at the end of the 2005 season.

There was almost no controversy when the owners ratified the competition committee recommendation Wednesday to make excessive celebration a 15-yard penalty. The vote was 31-1, with Oakland dissenting.

The change was aimed more at group celebrations than at individual ones — spikes, dunks and Lambeau leaps are still allowed.

The new penalties are aimed at staged photo snaps, circle dances and similar celebrations that previously were punished only by fines. The fines went up from 18 in 2002 to 61 last season, leading the committee to decide that the wrath from their coaches after a 15-yard walkoff would be more effective in curbing the demonstrators than the loss of money.

Other rules changes, most of them minor, include:

l Allowing wide receivers to wear the numbers 10-19. In the past, they could wear them only when all the numbers in the 80s were taken.

l Expansion of practice squads from five to eight players.

l Allowing the head coach to call a timeout by signaling to any official on the field. In the past, a player had to call the timeouts.

l Stopping the clock as soon as a punt hits the end zone. Previously, the clock didn’t stop until the ball was whistled dead.

l Making it illegal for a receiving team to advance the ball once a fair catch has been signaled. In the past, they could advance the ball if it hit the ground. The exception is if the kicking team touches the ball first.

l Extending the five-day period immediately after the season ends for interviewing assistant coaches to seven days, or the conclusion of the wild-card round. The policy also now will cover high-level front office positions.