Last Sunday, rookie running back Todd Gurley burst onto the NFL scene with a monster 19-carry, 146-yard day on the ground. Given his 7.7 yards per carry mark for the game, you would expect that Gurley did most of his damage with very good six- to nine-yard runs, mixed in with a couple of stuffs and a few monster plays.

Turns out that you would be wrong. In fact, not a single one of Gurley's runs fell within the six- to nine-yard range. Actually, four of his carries, or 21.1 percent, went backwards. Another five, or 26.3 percent, resulted in a gain of two yards or less. Another five went for three to five yards. The remaining five all went for at least twelve yards.

This feels like the norm in the NFL today. It feels like the five-yard run is an endangered species, and running backs are becoming increasingly dependent on the 20-plus-yard runs to keep their yards-per-carry numbers respectable.

But as Peyton Manning, who has managed to lead the Denver Broncos to a 5-0 record without any feeling in his right fingertips, would probably tell you, "It's not all about the feeling." So are NFL rushing plays really trending in a more extreme direction, or is that just our imagination?

The following charts illustrate the distribution of yards-per-rush-play in each of the past four seasons (including this one):

At quick glance, each of the charts seem to have just about the same shape. However, a closer look seems to imply that the 2015-16 graph has some key differences.

Let's zoom in on the three- to six-yard range:

Rushes for each yardage value between three and six have been less frequent this season than in each of the previous three. Overall, rushes of three to six yards are down to 32.04 percent, three percent less than the 35.05 percent average of the 2012-15 seasons.

All of those rushes have to go somewhere. This season has thus far marked a four-year high in rushes for negative yards, no gain, nine yards, and ten or more yards. These numbers confirm that our feelings were correct. Take that, Manning!

The increase in the rate of "extreme" rushes is not the only trend the NFL is seeing in the running game. This season has also seen a four-year low in both carries per game and yards per carry:

It is very possible that all of these trends are related. As teams run less and less, running backs are given fewer opportunities. This puts pressure on running backs to make the most of the carries they do get. Therefore, rather than running in a way that will maximize the expected yards, they are running in a fashion that will maximize their chances at a homerun. When they manage to evade the defender or break a tackle, it's off to the races. However, they also leave themselves susceptible to being bottled up near the line of scrimmage.

Of course, this is just one potential theory. Feel free to interpret the numbers as you will!