There's a certain order to the chaos at the line of scrimmage, and after a few hits, tailbacks begin to make some sense of it, Virginia's Kevin Parks said. It's usually a game of trial and error. A few hits, a few near-misses, and then it becomes clear.
In other words, ask most running backs what they need to break a big run, and the answer is simple: Just a few more touches.
"Once you get out there and the ball in your hands, it's natural," said Parks, who racked up 1,031 yards on 227 carries last year, both tops among returning ACC tailbacks. "You're getting in the flow of the game. You're taking your hits and get stronger as the game goes on. Some guys are like that."
Of course, some guys aren't. In fact, finding a true every-down back is a rarity these days, even at the NFL level. The position has become more specialized, and as that's happened, the need for a deep and diverse stable of backs has grown.
Even Parks, one of the league's true bell cows at tailback, doesn't figure to be the only show in town for Virginia. Sophomore Taquan Mizzell, one of the Cavaliers top recruits under coach Mike London, is right behind him on the depth chart, providing a dynamic change of pace for the offense.
The same is true at Louisville and UNC and Syracuse and Pitt (which has a pair 0f 700-yard backs returning) and nearly every other program in the conference. At Florida State, where Jimbo Fisher has given a tailback 25 carries in a game just four times during his tenure, Karlos Williams is the epitome of an every-down back, but even he's being challenged by freshman Dalvin Cook and sophomore Mario Pender -- neither of whom have taken a snap at the college level.
It's really a game of probabilities, Fisher said. Depth provides alternatives, and at a position where physical punishment comes with the territory, it's best for teams to be prepared with a contingency plan.
"A running back only has so many hits in him," Fisher said. "The durability, the freshness in the fourth quarter, developing depth on your team and if guys have certain skill sets you have to put them in position to have success like that. I think it helps your team grow."
Fisher certainly has the evidence to back up his theory. During the past two seasons, only Oregon and Ohio State have averaged more yards-per-carry (excepting sacks) than Florida State's 6.40 mark. Last season, the Seminoles averaged 6.33 yards-per-carry in the second halves of games, too — the fourth-best mark in the country and an improvement of more than 1.5 yards per touch from its first-half average.
Specialization and distribution have become paramount, even for programs that have traditionally relied on a lead ball carrier.
Rod McDowell racked up 189 carries for Clemson last year, but Dabo Swinney said that was more a factor of necessity than desire. With four running backs vying for carries on this year's depth chart and coordinator Chad Morris aiming to run at least 85 plays a game, the rushing attempts figure to be portioned out in smaller doses in 2014.
"It's really become a specialized position," said Swinney, who plans to have a backfield-by-committee approach this season. "You need different flavors. You don't want all vanilla ice cream. You need some strawberry, chocolate, blueberry."
Nationally, just 15 running backs averaged 20 carries per game last season, half the number to reach that average in 2007. But including QBs, there were 36 runners who averaged 6.5 yards-per-rush or better last season, nearly double the total from 2007.
There are still a few every-down ball-carriers, but they're the exception. Andre Williams accounted for 68 percent of Boston College's rushing attempts last season and ended the year as a Heisman finalist, but Parks was the only other ACC runner to carve out more than a 40 percent share in his backfield.
Duke Johnson certainly would've eclipsed that total at Miami, but he went down with an ankle injury in Miami's eighth game and was lost for the season. Johnson figures to return to a prominent role in 2014 -- perhaps the closest thing the ACC will have to a true bell cow -- but last year's injury showcased just how crucial it is to have depth. With a healthy Johnson, Miami averaged 5.4 yards per carry and 200 yards per game on the ground. Without him, the Hurricanes mustered just 3.6 yards per carry and less than 100 yards per game rushing.
Spreading the wealth even when there's a clear No. 1 on the depth chart helps build depth that might not have been there before, NC State coach Dave Doeren said. The Wolfpack figure to give at least three — and maybe four — tailbacks a share of the pie this year, and while Doeren said he'll play the hot hand on a series-by-series basis, the knowledge that each player will get his shot while not being guaranteed anything more has had a positive effect on practice.
"When you have two or three backs, they've got to maximize their carries and put themselves in a position to get more," he said.
The game of mix-and-match tailbacks doesn't always sit well with players who, like Parks, would love a chance to get into a rhythm and take a few hits, but it's a fact of life most have gotten used to.
"It's a hard thing when you get your mojo running and you get pulled," Parks said, "but at the end of the day, you've got to be a team player. If the coaches feel you're hitting on all cylinders, they'll keep you in."
And there's an advantage for them, too. All those hits may help a tailback get a feel for the game, but they're also a lot of wear and tear on players who are hoping to still have plenty of spring in their steps when it's time to play at the NFL level.
"It means they have more tread on the tires when they get to the NFL and can truly make money," Fisher said. "But you're still getting the most out of them while you're here."