PITTSBURGH — Don't expect the Pittsburgh Steelers' defensive linemen to look downfield very often when they face the Atlanta Falcons, even if Michael Vick or Warrick Dunn takes off on a long run.

They'll be too busy protecting themselves from one of the league's most aggressive blocking teams — a Falcons offensive line that has been criticized by at least three teams in the last year for its cut blocking techniques.

"You have to be ready for it," Steelers defensive end Brett Keisel said. "You have to understand that's what they're going to do. If you're not, you're going to get cut and you're not going to make the play."

The Steelers (2-3) also occasionally employ the technique, in which an offensive lineman blocks below the waist — normally, at knee level — to force a defender to drop his hands and, at times, sweep him off his feet.

The Falcons lead the NFL in rushing by a wide margin and are renowned for mastering the scheme. Titans coach Jeff Fisher complained to the NFL about the Falcons' blocking last year, and the Carolina Panthers were upset when two defensive linemen were hurt after being cut blocked by the Falcons. Tampa Bay also was unhappy with how the Falcons blocked.

"Yeah, it works," Keisel said. "They're the top rushing team in the league."

The Denver Broncos were among the first teams to popularize cut blocking, when Alex Gibbs was their offensive line coach. Gibbs has been a consultant to Falcons coach Jim Mora for two seasons after installing the blocking scheme as Atlanta's offensive line coach in 2004.

That same season, Steelers coach Bill Cowher criticized the Broncos for going over the line with their blocking after Denver offensive lineman George Foster broke Cincinnati defensive lineman Tony Williams' ankle by driving at him below the knees.

"It's a very competitive game that we play, but within that there are certain lines you don't go over," Cowher said.

Cowher's criticism surprised Denver coach Mike Shanahan, since the Steelers and Broncos did not play that season. Shanahan subsequently staged a film room session for Denver reporters, showing how the Steelers — All-Pro-guard Alan Faneca in particular — also employed the technique.

The Falcons (3-2) have used it while rushing for 1,160 yards in five games. No other team has rushed for more than 791 yards.

Dunn is fourth in the league with 511 yards, averaging 5.2 yards per carry, while Michael Vick is 16th with 401 yards but has a league-high 8.7 average. He is on pace to break Bobby Douglass' quarterback record of 968 yards rushing with the Bears in 1972.

"They're crazy, aren't they?" defensive end Aaron Smith said of the Falcons' ability to run. "It's ridiculous. You have Vick back there who can scramble for 50 yards at a time, and then you have Dunn who is a great running back. It's like a two-headed dragon."

Because the Falcons run so much, the Steelers are aware they must be alert on every play for a blocking look they may not have seen before.

"They get away with a lot of stuff cut blocking," Keisel said. "I think there are a lot of high-lows and things like that, but the refs don't see it because it's congested in there. That's the way the league is everywhere — it's not just Atlanta, everybody's cutting. It's part of the game."

The high-low tactic Keisel referred to is known as chop blocking, in which one player takes out a lineman while another is engaging him in a block. Chop blocking is a penalty, but is rarely called.

"You have to account for it when you're out there," Keisel said. "Your have to understand that's part of their scheme. And you'd better get your hands down or your legs are going to be scuffed up pretty bad."

The Falcons line will have a different look Sunday because left guard Matt Lehr drew a four-game suspension Tuesday for violating the league's substance abuse policy.