In 2008, Football Outsiders unveiled their "Speed Score" metric. The Speed Score is determined thusly:
The formula for the adjusted 40 score is (Weight * 200)/(40 Time^4). The multipliers are as such in the formula to ensure both accuracy as well as simplicity -- the scores that result revolve around a 100-point scale. The average adjusted 40 score of all running backs is 98.5; for all drafted running backs, it's 102.4; for all running backs selected in the first round, it's 112.1. Consider adjusted 40 score to be a sort of speed score -- a higher number is better.
Last year, FO.com wasn't so forthcoming with all of their speed score numbers so using the formula above I calculated them myself. I'm a modern day John Nash, yet I have the practical sense not to leave a baby to fend for itself in a bathtub full of water. If you remember, the 2008 running back class was armed to the teeth with talent. Peep the speed scores from 2008 (some of these scores vary slightly from the FO.com scores posted in their article - most likely due to the official/unofficial nature of the times as they are reported):
Chris Johnson led the pack and then lit up the NFL in 2008. The other big guns (McFadden, Mendenhall, and Stewart) rounded out the top 4. Six players graded out as first round material via the speed score (112.1 and higher) while an additional 10 players were deemed worthy of a draft pick. And aside from the Steve Slaton anomaly, any running back that was worth his salt in the NFL last year clocked a speed score of at least 102.
I tend to focus not on the guys with the "acceptable" scores but the highly graded guys that don't necessarily meet the mark. This year, there are a frightening number of highly graded players that don't even meet the grade of drafted running backs (102.4). Donald Brown (101.5), Shonn Green (97.1), and Knowshon Moreno (96.1) all grade out as potential first and second rounders, yet their performance indicates they shouldn't be drafted at all. Now, straight line speed isn't the be all and end all here, other skill sets such as quickness (stop and start), agility, and power factor into the success of a running back. A low speed score might motivate the scouts to fire up the old game tape to search for other defining skills. Just to scare everyone who loves any of the above players, Tony Hunt registered a 98.8 based on his combine numbers (eek).
The top guy this year, Andre Brown
is a name he Birds might be interested in kicking around. Brown was one of the most impressive running backs at this year's Senior Bowl, can catch the football, and has a lot of tread left on his tires. Kory Sheets
is another guy who had an impressive Senior Bowl, and definitely passed the eye test in Indianapolis. A guy I think a lot of us like, LeSean McCoy
didn't run due to the flu.
Just remember. FO.com only uses combine times in calculating their speed score numbers. Brian Westbrook ran a 4.57 at the combine and followed it up with a 4.37 at his pro day. Additionally, congratulations to Reno Mahe as his record low speed score of 82.5 remains intact for another year!
Historical speed scores for Birds' running backs:
Westbrook (Proday): 109.68
Westbrook (Combine): 91.71