NEW ROTOWORLD BETA SITE

Jonathan Bales

Fantasy Fallout

print article archives RSS

Exploring Running Back Size

Wednesday, April 2, 2014


The fact that heavy running backs are much worse than lighter ones isn’t surprising when you consider the differences in speed. So does extra weight hurt a running back? No, with two caveats: 1) he isn’t just eating Wendy’s and the “extra” weight is lean muscle and 2) his speed remains unchanged. I’ll take a 220-pound back with 4.45 speed over a 200-pound back with the same speed all day. Weight is good, it’s just not as important as straight-line speed.

 

Now, let’s get back to height…

 

 

Height and Running Back Success

 

The correlations suggested that, as a general rule-of-thumb, taller might not be worse for backs, but there’s another way to analyze the data - sorting it into buckets. I like to do this because it helps see how performance changes at certain thresholds. And when we do that with height, we see a different story for running backs.

 

I sorted all of the data into quantiles for height, weight and BMI.

 

RBH3

 

 

We see a steady decline in YPC with weight; the lightest quarter of all backs has been the most efficient, followed by the 26th-50th percentile, and so on. The BMI effect is similar, with a very rapid decline after the bottom quarter.

 

Very quickly, I want to mention that there’s probably a little bit of a selection bias here with lighter backs getting a higher quality of carries. When a running back gets a carry on third-and-10, he usually gains a decent number of yards, and he’s also usually a fairly light third-down back. However, such carries are pretty uncommon and the results are very strong, suggesting that the real culprit is simply heavy backs being slower.

 

I’m going to bold this sentence and say it again: the best running backs are fast.

 

Now, look at height. Remember that the correlations showed that height might not matter too much for running backs, but what we really see is that the bottom 75 percent of running backs in terms of height perform right around the same in terms of efficiency. Meanwhile, the top 25 percent - the tallest quarter of running backs - have rushed for fewer than 4.0 YPC since 2000. That’s horrific.

 

To me, this is clear evidence that height doesn’t matter all that much for running backs … to a point. And that point is right around 73 inches, or 6’1”.

 

Now let me just address the criticism sure to come to everyone’s minds: BUT ADRIAN PETERSON IS 6’1”! Yes, that’s true. As is the fact that Arian Foster ran a 4.68 in the 40-yard dash, Jerry Rice was also quite slow, Warren Sapp dominated inside despite shorter-than-average arms and lots of other cases of players becoming exceptions to the rule.

 

My goal isn’t to get every prediction correct, but just to tilt the odds a little bit. And the numbers suggest that, as a general rule-of-thumb, we should prefer shorter backs over those who stand well above 6’0”. That doesn’t mean we need to avoid every tall running back. In the case of Adrian Peterson, it’s kind of difficult to hate a 217-pound back with 4.40 speed. But if another back were similar to Peterson - 217 pounds with 4.40 speed and a comparable skill set - but he checked in at 5’10”, we’d be smart to favor the shorter back.

 

All other things equal, we should seek running backs 6’0” or shorter.



12
Jonathan Bales is the author of the Fantasy Football for Smart People book series and founder of RotoAcademy -- a fantasy football training school. He can be found on Twitter @BalesFootball.
Email :Jonathan Bales



Highest Searched Players over the last 7 days



Video Center

  •  
    Player News: Week 11

    Player News: Week 11
  •  
    Dose: The Return of RGIII?

    Dose: The Return of RGIII?
  •  
    DFS Analysis: Lewis, Johnson

    DFS Analysis: Lewis, Johnson
  •  
    Dose: Jones Could Miss Week 11

    Dose: Jones Could Miss Week 11
  •  
    Dose: Bell Doesn

    Dose: Bell Doesn't Show
  •  
    Dose: Watkins Expected Back

    Dose: Watkins Expected Back
  •  
    Nicole: Trade Targets

    Nicole: Trade Targets
  •  
    NBA Waiver Picks

    NBA Waiver Picks