Size Does Matter: How an NFL Player's Height and Weight Affect Performance

(Photo by Chris McGrath/Getty Images)

 
There’s a slight correlation between height and rushing touchdowns, taking out the jump (again) from 74 to 75 inches, that suggests touchdowns fall as height increases.

We also see a very interesting pattern when looking at weights and fantasy points. There’s a downward trend when it comes to the odds of finishing in the top quarter as weight increases. Why?

The answer is fantasy points. Because of their subjective weights (10 yards for one point, six points for a touchdown), the average running back in the sample had 70 percent of his fantasy points come from total yards, which, obviously, benefits the small backs with a lot of yards but just a few scores.

Continuing on with the predictive value of height and weight, the difference between a 5'8" and a 6'3" running back is 5.9 fantasy points in 250 attempts—an advantage to the smaller back by less than 51 yards and three-tenths of a touchdown. (Yes, the coefficient for rushing touchdown percentage was negative, but so small that it’s negligible.)

When looking at weights, we see that the lighter backs have a 2.39-fantasy point and an 18-yard edge over their heavier counterparts, while the heavier rushers have a 0.55-touchdown difference.

Unlike quarterbacks, height and weight seem to show the same conclusions for running backs, that shorter, smaller backs perform better. Thus, looking at BMI—which divides weight by height—will essentially neutralize the height/weight issue.

(This, in fact, is true, as the difference between the highest and lowest backs in BMI is less than one fantasy points, five rushing yards, and one touchdown.)

For running backs, we need to multiply height and weight, to combine them into one statistic.

When we do this, we find that the difference between a 68-inch, 200-lb. and a 75-inch, 250-lb. back is 5.79 fantasy points and 46 yards in favor of the lighter back and less than four-fifths of a touchdown in favor of the heavy runner.

Nevertheless, this is what we expected in the first place: smaller backs get the yards, and the bruisers get the scores. In terms of fantasy points, the differences in rushing yards and touchdowns are nearly equal, but the five-plus advantage in fantasy points for the small guys comes from their receiving.

In addition, another thing that may benefit the smaller rushers is the fact that yards may be a greater function of skill than touchdowns, considering that it only takes a good quarterback to move the offense into the five-yard line for a back to get a score.

Think about getting a small, fast runner like Leon Washington instead of a bruiser like Le’Ron McClain or Tim Hightower heading into the latter rounds of your draft. Washington’s receiving, as well as the fact he may get a few gratuitous touchdowns, may vault him over McClain or Hightower.

Now, let’s look at receivers—both wideouts and tight ends. Here are the statistics of each group of receivers.

 
There’s a clear correlation between measurables and production for wide receivers, and it’s not what you may have thought: shorter, smaller receivers perform better than taller, larger wideouts.

Shorter receivers have a higher yards-per-catch than taller receivers, though the pattern isn’t as noticeable as the relationship between weight and YPC; we see that yards-per-catch falls each and every time weight increases. The difference between the lightest and heaviest wideouts is 4.37 YPC, which equates to over 300 yards for a starter with 70 catches.

Keep in mind that those extra 30 fantasy points were the difference between the Nos. 8 and 19 receivers in terms of fantasy points, and the 300 yards were the difference between the Nos. 6 and 21 receivers in receiving yards last year.

There is, however, a slight positive trend regarding height and touchdown percentage, in that taller receivers have a small benefit over shorter ones. But the effect of height on touchdowns doesn’t cancel out yards per catch—smaller receivers still have more fantasy points per catch than taller wideouts.

That doesn’t hold steady, though, when looking at weight and touchdowns; there’s no relationship whatsoever between the two variables.

Now we'll examine the chance of producing a season in the top quarter, including only those receivers with 60 receptions.

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