This summer, it's the case-in-point for one offseason of living in the weight room.
With position coach Edgar Bennett barking encouragement, each running back — one at a time — must explode into a blocking sled and drive it along the sideline for a few yards. Lift and push.
The task was a daily struggle for Jackson as a rookie last year. His squatty, tree-trunk thighs couldn't compensate for a kicker-built upper body. All Jackson could do was bob the pad up and down while other backs plowed it forward. This shortcoming became a red flag in 11-on-11 segments, when Jackson was consistently bench-pressed into quarterbacks — his blitz pickup nothing more than a speed bump for linebackers.
So Jackson did something about it.
In his first full offseason, Jackson committed himself to the Packers' offseason training program and put on 10 pounds of muscle — going from 210 pounds to 220. As Ryan Grant's contract holdout seems to sink further into the abyss, Jackson has assumed the No. 1 role.
His increased strength is obvious in stature, and a comfort level in the team's instinct-driven, zone-blocking scheme has grown from an in-depth self-diagnosis in the classroom.
"He committed to our offseason workout program in the weight room and the film room," Bennett said. "He has done a terrific job, or fantastic job I should say, of taking care of his body as well as getting his mind right."
Through OTAs, minicamp and now training camp — as Grant's situation evolved from nuisance to concern — McCarthy has praised Jackson with regularity. He went as far as to call Tuesday night a "special" practice for Jackson.
"I think Brandon Jackson has had a good week," McCarthy said Wednesday. "I think he's been exceptional, particularly in the screen and draw periods. Things like that, those schemes are tailored to his running style."
Jackson's shifty, stop-and-run flair at Nebraska appeared to be a perfect fit for the Packers' one-cut zone scheme. But for someone who started only one season in college, the sudden promotion to No. 1 back last year was too much, too fast. Jackson was hesitant in his three starts, amassing only 97 yards on 38 carries (2.6 average.). A shin injury against San Diego sidelined Jackson for four games, and when he retuned, Grant had seized the starting role.
Just like that, it seemed like Jackson had spoiled his opportunity.
"It was just like balls coming at you, dodging and ducking," Jackson said. "Now, I'm just being under control and taking it one day at a time."
Overuse in camp attributed to Jackson's sluggish start to 2007. His rookie treads were not prepared for an unexpected pounding. Vernand Morency and Noah Herron sustained camp-ending knee injuries and DeShawn Wynn made only cameo appearances with a charade of ailments. Even P.J. Pope missed time with a knee injury.
Thus, Jackson became the de facto starter. And No. 2. And No. 3 back.
"There's a lot of running backs in there now, so if you need a little break, there are guys here," Jackson said.
With a healthy quartet of backs — Morency, Herron, Wynn and Kregg Lumpkin — in the fray to soften the workload, Jackson has been a gem in a training camp stuck in Favre-Thompson muck. He's hitting holes with more authority — mirroring his 113-yard performance against Detroit in Week 17 mop-up duty.
"He's stronger, aggressive and attacks the defense," Bennett said. "He's very crisp on his cuts and his reads and is making good decisions."
Unlike last summer, it doesn't feel like someone punched the fast-forward button every practice.
"Everything is coming into place," Jackson said. "It's slowing down. It's about being under control and understanding where to go."
Possibly Jackson's most obvious improvement was his patience during the team's screen-pass segment, as McCarthy noted.
The Packers' 2007 season could have ended a lot differently with one simple screen. At the end of the first half against New York in the NFC championship game, Jackson caught a screen and turned upfield and to the outside prematurely, allowing Antonio Pierce to make the tackle. A pinch of patience could have taken the play to the house with Jason Spitz, Daryn Colledge and Scott Wells in front of Jackson with nothing but green pastures in the way of a 14-6 halftime lead.
Naturally, Jackson said the screen game was his main focus this offseason.
"Just being under control. Patient," he said. "Last year, I was a little rushed, getting out too soon. I'd get out quicker than the guards. Now, I'm just being patient."
Screen passes and blitz pickups are handy perks of the job, but honestly, could Jackson fulfill Grant's role in the long-term? Bennett gives his answer before the question is finished.
"I think he can be an every-down back," Bennett said. "He's certainly capable of doing that. With everything he is doing on the practice field right now, he's making the most of his opportunity."
Jackson seconds that notion.
"Last year everything was thrown at me and it was a learning curve," he said. "Now, I'm ready to take it."
At one point during Monday's practice during the sled drill, Jackson stepped up to the pad and hit it once without driving it, misinterpreting Bennett's instructions.
Jackson smiled, laughed off the misunderstanding and slammed into the pad at full tilt — bulldozing it for 5 yards.
What a difference a year makes.
Tyler Dunne is a regular contributor to PackerReport.com and Packer Report magazine. E-mail him at email@example.com.