EUGENE -- When Gary Campbell speaks of using the spring to improve Oregon running backs' "drive," he's not talking about their motivation, only their motor.

"Looking back at all the footage from last year there were several opportunities to break some big runs where we just didn't drive through tackles," Campbell said. "It's just a matter of piston-driving legs when you're in traffic. When they're out in the open field, I don't care what they do. They can run as whatever's comfortable for them, but when they're in traffic, they've got to drive the knees. My thing to them is most people aren't great tacklers."

Campbell's importance on running with power and belief that tacklers aren't as good as they're made out to be is not a new strategy being installed this spring.

Senior Kenny Bassett has heard it all before, how churning legs are more difficult targets to grab onto. But he added Campbell is only spreading the gospel of high knee drive because it's a need that must be addressed.

"It's just spring ball and he's trying to get the young kids to get the right mindset," Bassett said. "We've got the right mindset here already but he's always trying to emphasize it every chance we get: Keep the legs moving."

The thinking inside the running backs' room is that by keeping their legs going, they'll keep yardage chains moving, too.

That running style comes most naturally to Thomas Tyner, the sophomore with a 211-pound frame -- the biggest of the backfield's presumed contributors -- and whose sprinting background on the track lends itself to high knee drive and explosiveness.

"The thing about him is I don't think he had the idea and he didn't even think about it, he just really came on at the end of the season and did more of that," Campbell said. "I think he's probably going to be the best guy at it because of his physicality."

Offensive coordinator Scott Frost also expects big things from Tyner in his sophomore season.

"If he keeps practicing like he is this spring, we're going to have a really good player on our hands," Frost said. "I think he's kind of decided to take it to the next level and it's showing up."

Byron Marshall and Tyner are competing for the No. 1 spot at the position this spring, after Marshall succeeded De'Anthony Thomas last season with aplomb to the tune of 1,038 yards and 14 touchdowns.

But when Campbell cross-examines those stats with Marshall's 2013 game video, he sees what could have been. He calls Marshall the back who stands to gain arguably the most from more broken tackles.

"Byron's got strong legs but he's one of the main guys that failed to do it several times in several games that cost him big runs," said Campbell, who is in his 31st season at Oregon. "I've really been concentrating on him in spring about getting his legs going.

"That happened once last Friday in practice. He was one tackle from scoring a touchdown and it was (Erick) Dargan just kind of grabbed him on the ankle and tripped him up because he was dragging his feet. That cost us a score."

Oregon set a school record with 7,345 yards in 2013 and welcomes back 10 of the 11 players who started the Alamo Bowl. Though the Ducks figure to be plenty offensive this fall, their coaches are spending their 15 spring practices attempting to wring out every last yard, a goal that has Campbell telling his charges to never give up on a play.

"It's a mental thing and you have to know that guys can't tackle instead of just accepting the fact that I'm going to be tackled, which a lot of backs do," Campbell said, slightly shaking his head. "They see a defender coming and think, 'OK, I'm going to be tackled.' I want the attitude to be that nobody's going to tackle me."

-- Andrew Greif