Introduction to these player comments
Index of player comments
Glossary of terms
Curtis Martin career statistics

Total touches (rushes + receptions) in first seven seasons

 1. Emmitt Smith         2682
 2. Curtis Martin        2670
 3. Eric Dickerson       2652
 4. Walter Payton        2447
 5. Thurman Thomas       2363
 6. Marshall Faulk       2360
 7. Barry Sanders        2335
 8. Ricky Watters        2300
 9. Jerome Bettis        2255
10. Earl Campbell        2144

Curtis is a workhorse, and so far the workload hasn't caught up with him. Someday, some combination of his workload and his age will get the better of him, but I'm not prepared to say when that will be. Anyway, Curtis' comment here is as good a place as any to study the effect of a high workload season on running backs.

Question 1: does a high workload season by an RB increase his chance of injury in the following season?

Question 2: does a high workload season by an RB decrease his fantasy output the following season?

The answer to both questions appears to be no.

Here's the study. I looked at all top-10 running backs from 1970 to 2000. I then divided that group of 310 backs into two subgroups: the 155 with the most touches (the "high workload group") and the 155 with the fewest touches (the "low workload group"). Then I looked at how many games they missed and how well they performed the following year. Here's the full data set.

• The high workload group missed an average of 1.67 games the next year
• The low workload group missed an average of 2.14 games the next year
• 59 percent of the high workload backs missed zero games the next year
• 47 percent of the low workload backs missed zero games the next year

These figures make it very hard to argue that a high workload increases a back's chances of injury in the following season. What's more, the high workload backs did not suffer from decreased production (in comparison to the low workload backs).

• The high workload backs saw their fantasy points per game decrease by 12 percent the next year.
• The low workload backs saw their fantasy points per game decrease by 16 percent the next year.

So tired legs and nagging injuries don't seem to be a real problem either. I then re-ran the study, but focused only on backs aged 27 and older. The results were similar. I then looked at only the extreme cases, the very highest workload seasons, but again found no evidence that those backs declined any more than their lesser-worked counterparts. I sliced and diced the data a number of different ways, but never found anything that would suggest that a single high workload season has a negative impact on a running back -- even an older running back.

Now, the extent to which multiple high-workload seasons eventually start to add up is another issue, but I'm having a hard time drawing up a statistical study that would shed any light on this.