My overall point is that in the case of Thurman Thomas, independent of coming off an injury, if he had carried the ball 300+ times, that 6.4 ypc would have dropped towards his 5.1 career ypc average. It's plain as day.
YPC averages tend to vary in a zig-zag, using the career ypc average as the baseline. YPC tends to zig-zag WITHIN the career arc of a bell curve. If a player has a high number of carries one season, he'll tend to benefit in a ypc bump the next season with fewer carries.
(FYI I didn't now that Thomas had a knee problem in 1986. Thanks for that context.)
Ok, I should move it back to attempts per game, because his 1985 season includes bowl stats and 12 games, whereas 1987 doesn't and is only 11 games.
So in 1985 he carried the ball 27.25 times a game. In 1987 he carried the ball 22.8 times per game. You're making the statement that 4.4 extra carries a game would make a 1.3 ypc difference in his entire average. Adjusting for the length of the season, that's 48 carries.
So 251 carries net 1613 yards to get that 6.4 average. If he had another 48 carries, that's 299 carries. 299 carries at a 5.1 average is 1525 yards.
So if additional carries would bring him anywhere near 5.1 ypc, he'd be averaging -1.8 ypc on those 48 carries. That's absurd and there's no reason to think that he's be losing yardage on additional carries. Of course, you didn't say it would drop TO his career average, you said it would drop
towards his career average.
Let's assume he merely averaged his lowest average season output, 4.1 ypc, on those additional 48 carries. That's reasonable, right? That would put him at 299 carries for 1809 yards, or 6.05 ypc. Nearly a full yard above his career average, so still an enormous increase, but not AS enormous.
But that follows your logic correctly. His apg went down, and his ypc went up.
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But that's Thurman Thomas. The Dayne example shows a range of 23.9 attempts per game to 28.1 attempts per game. Dayne's highest single season for attempts per game at 28.1 was also above his historical average. His second-highest number of attempts per game, 26.8 apg was his lowest ypc season.
In this case if you assume prior to 1999, Dayne was averaging 25.2 apg through three years at 5.74 ypc. His senior season he averaged nearly 3 more attempts per game and his ypc average went UP from 5.74 during his career to 6.03 ypc, or 0.3 ypc.
It goes against your previous assertion. His apg went up, and his ypc went up.
Your argument is that
if Wisconsin had limited him to 25.2 apg his average would have been higher than 6.03 ypc his senior season. I see absolutely no evidence for that. It's true that his freshman season he only got 25 apg, and he had a 6.5 ypc average. But his sophomore season he only had 23.9 apg, and a 5.5 ypc average.
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I just don't see evidence that ypc and volume are correlated positively or negatively within an individual player. In my mind it's still the player's natural talent, and then a whole bunch of external factors like usage, scheme, blocking, defenses faced, etc.