TERRE HAUTE, Ind. -- A small college defensive coordinator who has watched the Colts for years offered a quick scouting report. "The difference with the defense," he said, "is how everybody is running to the ball. You didn't see that type of hitting last year."

In most training camps, players go at three-quarter speed. Under new coach Tony Dungy, the Colts are going nearly all-out. The incredible shrinking defensive line is dropping pounds by doing bag drills and shooting the gaps between blockers. The young linebackers and members of the secondary may be making mistakes, but it's not noticeable because they are moving at such a fast pace. To fix a defense that finished No. 31 last season is points allowed, surrendering over 30 points a game, Dungy is unleashing the Colts.

	The Colts are expecting big things from rookie defensive end Dwight Freeney.

"Defenders are asked to go 100 miles an hour once the ball is snapped until the whistle blows," general manager Bill Polian said. "And that's every single player. The emphasis is on pursuit and the emphasis is on speed. That's a big departure from what the players are used to. In fact, we have some strained muscles because they are not used to doing as much running in camp. That will come."

Virtually every defensive lineman has dropped 10 to 15 pounds learning the frantic one-gap attack scheme of defensive line coach John Teerlink. The linebackers never stop moving. There is some danger in this approach. On one occasion early this week, halfback Edgerrin James, coming off major knee surgery, took a handoff over left guard. The linebackers and safeties attacked the hole like sharks, hitting him in the legs and knees, but James bounced right back to his feet and the defenders rushed into position for the next play.

Suddenly, quarterback Peyton Manning, who has little problem completing passes against the NFL's top defenses, is finding it more difficult to work his offense in practice. That brings a smile to Manning's face.

"It makes me throw more accurate passes," Manning said. "I like the way they preach the pass rush. They want sacks and they come off the ball. You know what it is when you hustle 100 percent. When you go full speed, it just seems the tipped balls come your way."

Manning is the biggest benefactor from an improved defense because it takes a lot of pressure off of him. Last year's defense gave up 357 yards a game and created only 25 turnovers. Giving up that much ground forced Manning into too many possessions inside his own 25-yard line. A defense that surrendered 30 points a game forced Manning to pass more and gamble for points. Consequently, he threw 23 interceptions.

Manning has established himself as one of the game's best quarterbacks. His offense is loaded and ranks in the top three annually. He expects to throw for 4,000 yards a year, and Polian loads up the payroll to keep the offensive talent base stocked with stars.

Polian knows the model of success for teams that invest 60 percent or more on offense: Find a defensive scheme that incorporates young players and use a cover-two zone pass defense that minimizes big plays and long touchdowns. The Rams hired one of Dungy's assistants, Lovie Smith, to teach that system. After changing as many as seven starters, the Rams went from one of the NFL's worst defenses to the third best last year.

The Rams went to the Super Bowl. If Dungy can cut eight to 10 points a game and 60 or so yards a game off the stats, the Colts expect to be in Super Bowl contention, too.

"Coach Dungy set our goals high," Manning said. "He wants our offense, defense and special teams to finish in the top five. You should have seen the special-teams practice the other day. Guys were flying all over the place. We're going to be good on special teams."

In some ways, the Colts' defense is deeper than the Bucs' defense Dungy inherited in 1996. Dungy installed his system and the Bucs' defensive ranking vaulted from No. 27 to No. 11. The Colts' defensive line is deeper, and the rest of the unit is loaded with young, fast athletes.

"I think our front is going to be quicker than that first year in Tampa," Dungy said. "At linebacker in Tampa, we had Derrick Brooks, Hardy Nickerson and Lonnie Martz. This group is more similar to the one we had in Minnesota in 1992. We played pretty well that year."

That Vikings team incorporated five new defensive starters and led the league with 28 interceptions. Four players made the Pro Bowl from that unit. This Colts defense may lack the stars, but Dungy plans to use the depth to keep players fresh and maintain a hectic tempo.

	"	Defenders are asked to go 100 miles an hour once the ball is snapped until the whistle blows. And that's every single player. The emphasis is on pursuit and the emphasis is on speed. That's a big departure from what the players are used to. In fact, we have some strained muscles because they are not used to doing as much running in camp. That will come. "
		— Bill Polian, Colts general manager

"You can turn the numbers around pretty fast," Dungy said.

What's noticeable is how much fun the players are having. Defensive end Chad Bratzke, a nine-year veteran, has dropped from 277 pounds to 260 under Teerlink's running, attacking style. He loves a defensive playbook that is about one-eighth the thickness of what it was under Jim Mora.

"He's nuts," Bratzke said of Teerlink. "He's the most positive coach, and he makes the most jokes. The bag drills are something else, too. I've learned so much from him and I've been playing for nine years. The system is great and it's not complicated. You have a lot of freedom to just go make plays and go get the quarterback."

Teerlink's biggest mission is making first-round choice Dwight Freeney an edge pass-rusher and second-rounder Larry Tripplett a nose tackle who can create havoc. Tripplett's sides are sore from the twisting and diving on Teerlink's demand.

"I'm loving it," Tripplett said. "When I got drafted here, I felt it was the perfect place for me. You've got to be an athlete in this system and break habits of just using your power. We're moving. We're darting. We're twisting our bodies, slapping, ripping ... I dropped about 15 pounds since I've been drafted and I'm down to 298 pounds."

Dungy says that Freeney has Derrick Thomas-type speed and a first step that is similar to the former Chiefs great. "It's going to be a matter of time before he puts it all together," Dungy said.

Cornerback Walt Harris watched the Bears' defense come together last year, propelling that team to the NFC Central title. How well he and David Macklin work at cornerback could determine whether the Colts can make a similar jump.

"As soon as we buy into coach Dungy's system, we will do well," Harris said. "We have talent here. I feel like we have more talent than we had in Chicago."

Polian put together the four Super Bowl runs by the Bills, but he took over a Colts team that was devoid of top athletes. Now the defense looks quick and athletic, and Dungy is reveling in the challenge of developing young players.

"We weren't big on defense in Buffalo, and there are no Bruce Smiths or Cornelius Bennetts on this Colts team," Polian said. "The Bills teams were athletic enough even though we played a 3-4. We're probably bigger here. Freeney has the speed and explosiveness to turn the corner."

The Colts know they finished No. 31 on defense last year, and they aren't happy about it. They know if they want to make a Super Bowl run, their defenders will have to sprint, not walk, to get there.

John Clayton is a senior NFL writer for ESPN.com.