SmashMouth

1. Emmitt Smith: 1,021 yards. Not bad. He followed up at age 33 with over 900 before falling off completely with Arizona and having a decent final year with 900+ at 35. Note: He never averaged 4 YPC once he reached 32.
2. Walter Payton: 1,333 yards at age 32. The next year he was a shell of that with 533 and was done.
3. Barry Sanders: Retired at 30. N/A
4. Curtis Martin: At 32, had 735 yards at a pretty poor 3.3 YPC and was out of the league the next year.
5. Ladainian Tomlinson: Ran for 280 yards with the Jets in his last season at age 32.
6. Jerome Bettis: Ran for 900+ yards at under 4 YPC. Had 368 the next year and was done.
7. Eric Dickerson: Ran for 729 yards at 3.9 YPC. Followed that up with 91 yards the next year and was done.
8. Frank Gore: Ran for 967 yards at 3.7 YPC. Followed up last year with 1,029 and 3.9 YPC.
9. Tony Dorsett: Ran for 748 yards at 4.1 YPC. Followed up at 33 with 456 at 3.5 YPC. And had a very forgettable year in Denver before he retired.
10. Jim Brown: Retired at 29. N/A
11. Mashall Faulk Ran for 292 yards at age 32 his last year.
12. Edgerrin James: Retired at 31. N/A
13. Marcus Allen: Ran for 301 yards but actually improved over the next four years in KC averaging more than 800 yards per year. Retired at 37.
14. Franco Harris: Ran for 604 yards at over 4 YPC. Followed up at 33 with 1,007 but fell to just 3.6 YPC. Played one more forgettable year at 34 and retired.
15. Thurman Thomas: Ran for 381 yards. Had two more similar years before retiring.

Which leads to No. 16 Peterson. For the top 15 rushers of all time, excluding those who retired before 32, the average yards at age 32 is about 630 yards. Last year Hightower had 548.