Sprinting down the field on punt and kickoff coverage to create a car crash-level collision requires a special personality.

"You have to have no fear," safety Jeremy Thornburg said. "You have to have a screw loose in your head."

Whether the players occupying the Green Bay Packers' coverage units are sound in mind or not, they have performed effectively.

"We're getting as good as we've been here in our coverage units. I was so proud of our kickoff cover unit the other day," Head Coach Mike Sherman said. "That was a major component in order for us to win."

The Packers held Atlanta Falcons return specialist Allen Rossum, a 2005 Pro Bowl return specialist and a former Packer, to five returns at or inside his own 20-yard line.

"That was probably our best day in my nine years," kicker Ryan Longwell said. "It was a pretty dominant performance."

The special teams needs to come up with a similar effort on Monday against the Minnesota Vikings. The New York Giants outgained the Vikings 405 to 137 in total yardage on Sunday, but the Vikings won 24-21 in part because of their big plays on special teams. Wide receiver Koren Robinson returned a kickoff for an 86-yard touchdown, and running back Mewelde Moore returned a punt for a 71-yard touchdown.

"They're coming in with confidence obviously having two returns for touchdowns," Thornburg said. "We know we have a challenge coming our way."

The Packers, however, have found the right ingredients to take on that challenge.

"We've got a good mix of guys on our coverage team," Longwell said. "We've got the right mix of speed versus size."

Two players, in particular, rookies Thornburg and Brady Poppinga, have brought that mixture of size and speed to special teams. Poppinga, an explosive outside linebacker, leads the Packers with 18 special teams tackles while Thornburg's knack for throwing his body around on that unit led the Packers to claim him off waivers from the San Francisco 49ers on Nov. 2. Thornburg has made a special teams tackle in both games he has played.

"Thornburg has helped us," Sherman said. "Some of these younger guys are stepping forward. Poppinga has made some plays."

On punt returns Thornburg takes out the man protecting the punter. A right end on kickoff returns, he must occupy the outside blocker. Poppinga plays left tackle on punt coverage and is fifth person on the left side during kickoff returns. Both players have taken to the reckless abandon needed for that role.

"I love it," Thornburg said. "It's how I earn my paycheck."

The return unit is only part of the reason for the Packers' success. Both Longwell and punter B.J. Sander have done a solid job -- particularly against the Falcons -- of pinning their opposition back.

"Our kickers are part of that," Sherman said. "If you don't have hangtime or location, it's hard to cover a kick."

The Packers placed extra emphasis on special teams this offseason, drilling the players in technique during minicamps, opportunity sessions and the preseason. Those instructional periods helped, but it took half of the season for the players to become truly comfortable with their roles.

Before the season Thornburg had not played special teams since his freshman year at Northern Arizona. Although Poppinga played on the punt team a few times during his junior year, he has not played regularly on special teams since his freshman year either. They had to learn how to break through the double teams, chips and traps.

"A lot of these kids come out of college, and they don't play special teams in college because they're the star player," Sherman said. "Special teams is a new element to them."

They also had to learn their teammates. Playing special teams is analogous to how a piece of elastic stretches. When you pull on one side, the other must constrict. Each special teamer must compensate for his teammates when staying in specific lanes to funnel the returner in.

"Covering kicks is the toughest thing to practice because you don't really get accustomed to what the guy's doing next to you," Longwell said. "That's stuff you can only learn on the job. With a younger group, it's taken us a little longer."

Now behind two young rookies, the Packers have become a cohesive unit confident in their ability to stop even the most capable returners in the NFL.

"We all have our part," Poppinga said. "It takes all 11 of us to do the job."