40 Yard Dash and Speed Scores

What do running backs have in common with bowling balls? The bigger and faster they are, the more force they produce on contact. A 15 pound ball traveling at 20 mph will usually knock more pins to the backboard with more force than a 10 pound ball. Similarly, a 230 pound running back running a 4.4 in the 40 yard dash will run over more linebackers and safeties than a 190 pound running back running at the same speed. Or so the theory goes.

That is what speed scores are all about. The Speed Scores for running backs are calculated by factoring in both a player's weight as well as his time in the 40 yard dash. The formula is basically to multiply the player's weight in pounds by 200. And take that number and divide it by the player's 40 yard dash time. Then take that number and raise it to the 4th power.

If you go to the following URL Speed Scores 40 yard dash, you will see how the Speed Scores for active NFL Running Backs correlates into actual production. Interestingly, there does not really seem to be much correlation between a higher speed score and higher yards per carry. However, there does appear to be a substantial correlation between higher speed scores and total yards overall throughout the season.

These results may be explained in a number of ways. One interpretation is that some running backs like Brandon Jacobs of the New York Giants have running styles that are very violent and lend themselves to wear and tear. Their upright and confrontational running style works well in their first two or three years or so, but those beatings start to add up. For instance, between seasons 2007-2008, Brandon Jacobs averaged 5.0 yards per carry and totaled over 1,000 yards in each of those seasons. However, in 2009, Brandon Jacobs' yards per carry dropped 26% to 3.7 yards per carry and only 835 total yards for the season. Currently, Brandon Jacobs has the highest speed score in the NFL.

Another interesting example is Minnesota Vikings Adrian Peterson Speed Scores 40 yard dash. Currently, Adrian Peterson's speed score is 14th best in the NFL with a 40 yard time of 4.40 and a playing weight of 217 pounds which equals 115.8. In 2007, his rookie year Adrian Peterson had 5.6 yards per carry with 1,341 total yards rushing. However, those numbers dipped a bit in 2009 with a 4.4 yards per carry average and 1383 total yards for the season. Between his rookie season and 2009, AP's yards per rush has fallen 21% in spite of a more vertical offense spearheaded by Brett Favre and Percy Harvin.

The examples of Adrian Peterson and Brandon Jacobs indicate that while a high Speed Score can be a good predictor of yards per carry early in their careers, the wear and tear on running backs can significantly the importance of a speed score as they enter the latter years of their careers. It should also be noted that the relatively upright and violent running styles of those two running backs contribute to the decreased significance of their speed scores. Barry Sanders, one of the greatest running backs to ever play once remarked that the most important thing he learned as a running back is to know when to fall down and how. In other words, he began to understand that a violent and upright running style is shortsighted.

You should also note that the NFL's all-time leading rusher, Emmitt Smith had a relatively pedestrian Speed Score of 96.5. Emmitt ran a 4.55 in the 40 at a playing weight of around 202. In today's NFL, Emmitt's speed score is somewhat mediocre in that the average NFL running back has a speed score of about 98.5. How did he do it? He certainly did not bowl people over with his power. He did it with technique. He hit the line of scrimmage at full speed. And his diminutive stature and low-running style (5'9") made it hard for defensive linemen and linebackers to locate him behind that massive offensive line. And when he was tackled, he always fell forward just as a Hollywood stuntman: carefully and efficiently.

Now, just in case you are ready to completely dismiss the Speed Score for running backs, you should also consider the case of arguably the greatest running back of all time: Bo Jackson. Anyone who had the pleasure of watching Bo Jackson play would tell you that he was better than Emmitt Smith, OJ Simpson, or Barry Sanders. What was his speed score? His speed score was 149.5 because he ran the 40 yard dash between 4.09-4.12 seconds at a playing weight of between 220-227 pounds. Bo Jackson's Speed Score is the highest recorded Speed Score in the history of the NFL. Today's leader? Brandon Jacobs with a Speed Score of 123.5. 40 yard dash