The whistle blows and the play is over, yet there's no time to relax with the way No. 6 Oklahoma attacks on offense.
The end of one play means it's time to move on to the next, as quickly as possible. Quarterback Landry Jones gets the play call from the sidelines, then hurriedly bounces from one lineman to the next to pass instructions along. Only a few seconds later, the ball is snapped.
If everything's clicking, the defense hasn't had time to set up yet.
This is no frantic 2-minute drill brought on by a late deficit. The Sooners (5-0, 1-0 Big 12) are just as likely to move at the ultra-fast tempo in the first quarter of a scoreless game, just as they did in scoring their first touchdown in the 28-20 Red River Rivalry win against Texas two weeks ago.
When the timing seemed right, they sped things up again early in the fourth quarter and scored another touchdown against an unsettled Longhorns defense.
"You can see it on the defense's faces," tight end James Hanna said. "They're starting to get confused or get tired from it."
Oklahoma first went with the hurry-up offense back in 2008, using it to score an NCAA record 716 points. Sam Bradford ran the controls with precision and landed the Heisman Trophy with the massive numbers he was able to accumulate through added snaps.
Last year, the fast-break offense was rarely a factor. Bradford and a slew of other offensive starters missed extensive time with injuries, and their replacements couldn't produce the same pace without costly mistakes.
In the offseason, finding that high gear again was a focal point. It started with getting players in the right condition to be able to play without breathers, then developed with rapid-fire repetitions in training camp.
"I feel like through two-a-days we definitely improved with our speed of it, and that helps tremendously because the defensive line can't get set, they don't know their calls, they don't know what to do," center Ben Habern said. "And it's proven on tape that you can tell we kind of gash defenses a couple times when they're not set."
DeMarco Murray had touchdowns from 19 and 20 yards — his longest runs of the game — against Texas. On one 29-yard pass play against Cincinnati, the Sooners snapped the ball with a whopping 27 seconds left on the 40-second play clock. That pass set up an early touchdown, and Oklahoma went back to the hurry-up pace on a 92-yard scoring march in the third quarter of the 31-29 victory.
Coach Bob Stoops said going faster in no way guarantees more points for Oklahoma. While the plays against Texas and Cincinnati show how lethal the attack can be, what sticks in his mind are the times that the Sooners tried to move so quickly that they confused themselves.
"I can go back and show you multiple times where we're unsure who to target because they're not lined up, so we let a guy go that we shouldn't have and then he's in the backfield messing the play up," Stoops said. "That has happened much more than I want it to."
Much of the pressure to get it right lands on Jones. He's charged with memorizing a set of quick plays that are put in place for each opponent. While the receivers get their signals from the sidelines, it's up to Jones to get himself and the offensive line ready to roll quickly.
"He's got to do everything he does in the normal tempo. He's just got to do it a whole lot faster," quarterbacks coach Josh Heupel said. "There's a lot of positives to it. I think the kids like playing at that speed.
"At the same time, it takes some time for the quarterback to develop the ability to think that quickly, see that quickly and react to things. So, there's a learning curve that goes along with it."
Texas coach Mack Brown said his players had been preparing for the hurry-up pace all week but still got "gassed" by it in the Red River Rivalry.
Paul Rhoads, Iowa State's coach, said he plans to put in place automatic defensive calls so the Cyclones (3-3, 1-1) don't have to wait for calls from the sidelines in Saturday's game.
And here's the scary part: The Sooners know they can still move even faster.
"It's definitely hard, it's definitely tedious. It's something that some guys don't want to do all the time," Habern said. "But the more repetition you get, the more it just becomes easier and easier. There comes point where it's almost like nothing to us. It's like reading the back of our hand. It's just second nature.
"When we get to that point, that's how we get even faster and that's how we can kind of gash defenses."
AP freelance writer Chuck Schoffner contributed to this report from Ames, Iowa.