In 1998, Atlanta Falcons running back Jamaal Anderson tore up the league with 1,846 rushing yards and 16 total touchdowns while carrying the ball an NFL-record 410 times. That's nearly 26 attempts per game.
The massive workload appeared to take a toll on Anderson; he played in only two games the following season and averaged just 3.6 YPC during the rest of his NFL career—a career that lasted only 21 more games.
Anderson's case is extreme, but not totally unusual; anecdotally, there seems to be a whole lot of evidence that running backs coming off of high-volume seasons tend to break down in some way the next year. If you ask the average fantasy football player if running backs break down after receiving lots of carries, he's going to respond "of course" and cite Anderson or some other back who garnered lots of touches and was never the same.
I broke down this concept in my first book, but I wanted to come back to it to 1) update the past data and 2) propose some unique thoughts on the subject. So do running backs really suffer after high-volume seasons? Let's take a look.
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The Data on Running Backs Breaking Down
Let me save you the suspense: the numbers are overwhelmingly in support of high-volume running backs regressing in the year following a heavy workload. Take a look at how 300-carry running backs from 2003 to 2013—of which there were 75—fared in the following year (Year X+1).
Massive drops—a 15 percent decline in games started and a 23 percent decline in touchdowns. That's pretty startling and of obvious concern for fantasy owners. Running backs coming off of seasons with 300-plus carries have scored exactly 2.5 fewer touchdowns in the following year, on average, which is 15 fantasy points—or about one fantasy point per game from touchdowns alone.
There are other declines in production, too. Take a look at the average number of attempts and rushing yards.
The typical 300-carry running back has seen a massive 22 percent decline in rushing attempts and an even bigger 25 percent drop in rushing yards. If you picked a 300-carry back out of a hat and were asked to predict his rushing yards in Year X+1, you'd probably have a pretty accurate projection if you just sliced his rushing yards by one-quarter.
Well, these numbers are pretty conclusive, right? As Lee Corso likes to say, not so fast my friend…
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Why the Numbers Are Misleading
When we're analyzing any sample of players, we need to ask ourselves if they're representative of the conclusions we draw and if there's any sort of selection bias at work. A selection bias occurs when the individuals we're studying are skewed in some way and not representative of the entire sample.
While there's not an inherent "flaw" analyzing 300-carry running backs to see if they become overworked, there's still a bias toward the type of running backs who reach that threshold of work. Namely, a running back needs certain things to go right for him to see such a heavy workload.
First, he needs to be healthy. Running backs get injured all the time, and I'd argue that no running back is ever likely to start 16 games in a season. That's just the nature of the position. So unusual health is basically a prerequisite for seeing 300 carries.
Second, they need to be efficient. A running back who is averaging 3.2 YPC after 10 games probably won't see a whole lot of carries moving forward. Thus, most high-volume running backs are rushing at a decent level of efficiency.
So what we're really looking at when we examine high-volume running backs is a group that's benefited from better-than-average health and better-than-average efficiency. Both of those things are influenced heavily by randomness, and thus likely to regress in the future. A running back who starts all 16 games is probably going to start fewer games in the following season whether he had a lot of carries or not. Similarly, a running back who rushes for 5.0 YPC is very likely to check in below that number in the next year, again regardless of his workload.
In effect, what we're saying is "running backs who are unusually healthy and probably have higher-than-normal efficiency will have worse health and efficiency the following season." That's pretty obvious though, right?
Here's how running back efficiency has tanked after a season with 300-plus carries.
Running backs who have rushed 300 or more times over the past decade have averaged 4.39 YPC during their high-volume season and just 4.18 YPC the next year—a small but meaningful drop of 4.8 percent.
But here's the key: take a look at the rushing efficiency for all players on all carries during that time. At 4.17 YPC, it's actually worse than the 300-carry backs in Year X+1. That suggests that backs aren't falling off of a cliff after seasons with high volume, but rather just regressing naturally. Since the sample of 300-carry backs is naturally skewed to include mainly just those backs with high efficiency and great health, we'd expect a drop in YPC and games played whether they get "overworked" or not.