The improvement in the Gophers' defensive pressure is caused by a lot of factors, the architect of that defense believes, stuff like better depth and weight-room discipline and better playbook comprehension.

But really, Tracy Claeys said, it mostly boils down to basic human nature.

"Eventually," the Gophers defensive coordinator says, "you get tired of getting your butt kicked."

The Gophers must have been exhausted.

It's a phenomenon Claeys has witnessed in previous stops on Jerry Kill's staff, and one that finally materialized, the coach said, during red-zone drills in spring camp. Coaches would put the football on the 5-yard line and issue a challenge: Score, and the defense does extra sprints. Hold, and the offense runs. "There's a winner and a loser in everything," Claeys said, "and eventually, you have to decide whether you're going to compete."

The defense did, and the defense has so far this year, and that improvement is largely responsible for the 2-0 record that the Gophers will put on the line Saturday against Western Michigan. The Gophers defense has allowed exactly half as many rushing yards as its offense has gained, allowed quarterbacks to complete only half their passes, and surrendered only one touchdown in regulation time in each of the first two games.

"We're definitely better this year," said sophomore end Michael Amaefula, one of eight defensive linemen who rotate in and out during the game. "On film, we can see a great push. We're moving people back 2 or 3 yards. And we're getting hits on quarterbacks when they use three-step drops, which usually doesn't happen much. But we're getting into the backfield to make those plays."

As everyone around the Gophers is quick to acknowledge, however, the defense's success has come against UNLV and New Hampshire, likely the two least talented teams on Minnesota's schedule, both of which used underclassmen at quarterback.

Western Michigan, by contrast, trusts senior Alex Carder to operate an up-tempo, multiformation attack that rolled up 631 yards against FCS-level Eastern Illinois one week ago.

In other words, study hall is over. It's time to take the test.

"Every time we take a job, we preach belief-without-evidence -- 'Believe that you're going to be good,' " Claeys said. "But hell, pretty soon you've got to see some evidence."

The evidence says the defense's improvement starts with the front four -- mostly because, on the Gophers, it's a front eight. Claeys and Kill are believers in a hockey-style approach to the pass rush, that using several players on short shifts is more effective than asking a 275-pound lineman to crash into the line for three hours.

"It's definitely working. It keeps our legs fresh," Amaefula said. "You go really hard for three, four, five plays, and the next guy comes in with the same mentality. After a few series, we can feel how much more energy we have than the offensive line, and we're getting into the backfield."

The Gophers didn't have enough depth and experience to rotate pass-rushers last year, Claeys said, but the improvement of sophomores Amaefula and Ben Perry, plus the surprising impact of true freshman Scott Ekpe, has made it possible.

Then there is the emergence of starting tackles Cameron Botticelli and Ra'Shede Hageman, 300-pounders who are commanding double-teams inside, which in turn allow the ends more room.

"Every [lineman] who comes after me," Hageman said, "opens a hole up for someone else."

Those holes have produced six sacks; the Gophers had just 19 all of last year.

With Western Michigan's Broncos averaging 45 passes per game, Hageman expects the Gophers's beefed-up line to add to that total Saturday. "Seeing how many times [Carder] throws the ball," Hageman said, "I'm excited to play them."

Excitement on the defensive line? For the Gophers, that's something new.