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Running the Numbers: Want an NFL RB? Look for Speed

When the Cowboys drafted running back DeMarco Murray in the third round of the 2011 NFL Draft, the selection was a better one than most of us believed. That's easy to say now that we've seen Murray, despite his injuries, have success in the NFL. But at the time of the pick, what reasons were there to believe Murray would be able to play the running back position at a high level in the NFL?

As the Cowboys formulate their board heading into the draft, their primary goal will be searching for value that others have overlooked. Just as Dallas needs to choose which characteristics they pay for in free agency (such as when determining Anthony Spencer’s market value), they also need to determine which traits they'll seek in regards to incoming rookies. To acquire value, those characteristics should be 1) undervalued by other teams and 2) predictive of NFL success.

Using Measurables to Predict NFL Performance

For rookie running backs, one of the best predictors of NFL success is straight-line speed. That alone will be a controversial assertion in a day and age when most believe teams already overvalue measurables such as the 40-yard dash. We all know the horror stories of teams over-drafting "height/weight/speed" players like Oakland's Darrius Heyward-Bey. For those against using anything but game tape to assess incoming rookies, there are typically two arguments put forth:

1) "Player X ran a 4.35 and was a bust and Player Y ran a 4.60 and was great."


2) "Football players never need to bench press and rarely run 40 yards in a straight line during games."

In response to the first criticism of measurables, we can always find individual cases that support our views. Emmitt Smith was one of the best running backs in NFL history and he probably never clocked in below 4.50 in the 40-yard dash. On the flip side, Auburn's Mario Fannin ran a 4.37 at 224 pounds at the 2011 Scouting Combine, but he has yet to record a carry in the NFL.

When we're trying to determine if certain stats or other quantifiable measures are useful in predicting NFL value, however, we need to do our best to not allow the success or failure of a single player drastically affect our views. Yes, Smith was able to overcome unimpressive straight-line speed, but there are lots of reasons for that, and Smith is really the exception to the rule.

In regards to the second criticism, it's certainly true that players rarely run 40 yards in a straight line, they're not asked to bench press during games, and, as far as I know, they're never asked to jump as far as they can off of the line of scrimmage. But it doesn't matter. All we're looking for is whether or not the results of certain tests can predict how a player will perform in the NFL. If they can, they're useful, even if the movements aren't conducted in games.

For some positions, many of the combine drills don't matter. It's not particularly useful to know how high a right tackle can jump, for example. Other times, the numbers are important. And sometimes, they matter a whole lot. That's the case for running backs and 40-yard dash times.

Running Backs and 40-Yard Dashes

It's common to hear that running backs need to be "quicker than fast," meaning how fast they can run long distances doesn't matter as much as how quickly they can move in short areas. Smith was a "quicker than fast" running back, and he obviously thrived with his ability to maneuver in traffic. While I'm not at all debating the fact that running backs do indeed need to possess short-area quickness, it's also true that the fastest running backs, as measured by the 40-yard dash, have had the most NFL success.


To the right, I charted the approximate value per season for running backs drafted from 2005 to 2009 (allowing a three-season gap to accurately assess value). I broke down the players according to their combine 40-yard dash times.

The results are obvious: speed kills for running backs. Of the running backs I charted, those who ran a sub-4.40 at the combine have produced at over six times the rate of those backs who ran 4.50 or worse. Five of the six backs to run sub-4.40, Chris Johnson, Darren McFadden, Jamaal Charles, Reggie Bush and Maurice Jones-Drew, have produced at a high level at some point during their careers, with just one player, undrafted Anthony Alridge, failing to find success. Jones-Drew was drafted in the second round and Charles didn't go until the third.

As with many positions, there appears to be a cutoff point that players must cross to have the necessary explosiveness to perform at a high level in the NFL. For running backs, that point seems to be in the range of 4.50. During the period I analyzed, only one running back, Frank Gore, ran below 4.50 and still posted an AV per season of at least seven. The second-best running back to run over 4.50 was Ahmad Bradshaw, a steep fall.

Meanwhile, the success rate of running backs in the 4.40-4.49 range has been far higher than those below 4.49. In that range, we've seen explosive backs like Adrian Peterson (4.40), Ray Rice (4.42), Matt Forte (4.44), and Marshawn Lynch (4.46) continually rank among the league-leaders in rushing during their time in the league. It's worth noting that the 40-yard dash also seems to predict running back success better than other drills such as the short shuttle and three-cone drill.

Cowboys' Options in 2013

As the Cowboys are scouting the available running backs this year, their goal shouldn't necessarily be to find a "complement" for Murray, but rather to simply draft the best available player. By emphasizing straight-line speed, the 'Boys can dramatically increase their odds of hitting on a running back. Again, that doesn't mean they should blindly select the fastest back, but instead weigh speed more heavily than other factors to increase the probability of finding a diamond in the rough.

Let's take a look at the top 20 official 40 times for the 2013 running backs to see who might be available for Dallas:

  1. Onterio McCalebb, Auburn: 4.34
  2. Knile Davis, Arkansas: 4.37
  3. Kerwynn Williams, Utah State: 4.48
  4. Johnathan Franklin, UCLA: 4.49
  5. Michael Ford, LSU: 4.50
  6. D.J. Harper, Boise State: 4.52
  7. Kenjon Barner, Oregon: 4.52
  8. Mike James, Miami: 4.52
  9. Giovani Bernard, UNC: 4.53

10.  Christine Michael, Texas A&M: 4.54

11.  Mike Gillislee, Florida: 4.55

12.  Zac Stacy, Vanderbilt: 4.55

13.  Matthew Tucker, TCU: 4.55

14.  Cierre Wood, Notre Dame: 4.56

15.  C.J. Anderson, Cal: 4.60

16.  Le'Veon Bell, Michigan State: 4.60

17.  Andre Ellington, Clemson: 4.61

18.  Joseph Randle, Oklahoma State: 4.63

19.  Montee Ball, Wisconsin: 4.66

20.  Theo Riddick, Notre Dame: 4.68

Notable: Jawan Jamison, Rutgers (4.68); Stefphon Jefferson, Nevada (4.68); Rex Burkhead, Nebraska (4.73); Stepfan Taylor, Stanford (4.76); Robbie Rouse, Fresno State (4.80); Ray Graham, Pitt (4.80)

Right out of the gate, you can see this is a very slow running back class. Since 2005, there have been an average of over seven running backs per year to run under 4.48. In 2013, there were two.

It's important to note that 4.50 isn't some magic cutoff line; it isn't like Johnathan Franklin is a much better prospect because he ran 4.49 instead of 4.50. Instead, it's really a range of potential, and the further you move down the list, the more you have to be concerned. By the time you get to highly-regarded running backs in the 4.60 range or lower – Le'Veon Bell, Andre Ellington, Montee Ball, Jawan Jamison and Stepfan Taylor – you have to begin to wonder if they have the speed to perform in the big leagues. Remember, Frank Gore is the only running back since 2005 to run 4.60-plus at the combine and still have legitimate NFL success.

On top of that, 40 times should be used as just one tool in the Cowboys' scouting arsenal. Lots of other factors go into drafting running backs, not the least of which is size. McCalebb has blazing speed, for example, but at 168 pounds, he simply can't hold up at running back in the NFL.

Having said that, Knile Davis, Kerwynn Williams, and Johnathan Franklin, all sub-4.50 runners, are interesting prospects. Davis is a 227-pound explosive athlete who was highly-productive in 2010 before suffering a season-ending ankle injury in 2011. Both Williams and Franklin are small, stocky backs who also turned in big-time numbers during their college careers, a trait the Cowboys seem to covet.

If the 'Boys value straight-line speed in running backs as much as they should, Davis, Williams and Franklin are all names to watch in the middle rounds, among others. Meanwhile, players like Bell, Ellington, Ball, Jamison and Taylor might not possess as much value as it initially appeared.

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