I made the mistake as a young pup of peaking too early.

In fourth grade, I balled out at four square. My agility was on point, and my hand-eye coordination was finally starting to round out. Things came easily that year.

Fifth grade started largely the same. I was able to get to that king square and hold court for a good chunk of each recess. I was feeling good.

But as the year went along, something wasn't right. I could feel my body start to deteriorate the further we got into the school year, and my performance dipped with it. Suddenly, I was hitting lines with more regularity, and I couldn't get my left foot out of the way quickly enough. By the end of the year, I had nothing left in the tank.

Even though the NFL season isn't nearly as grating on your physical condition as four square, I wouldn't be shocked if players experienced similar drop-offs as they aged. We've seen how much running-back production drops off as a whole as they age year to year, but do they see similar fall offs during the season?

This could have implications for your daily fantasy football decision making. If we can see a serious decline in production for older backs, that should influence how you value them when you're filling out your rosters. Is this something we actually need to consider? Let's take a look.

Method

In order to figure this out, I looked at the 50 running backs who produced the most fantasy points (based on half-PPR scoring) from 2004 to 2014. This was in order to give myself a large enough sample size without dipping into players whom you wouldn't really consider when filling out a lineup in a daily league.

After snagging those players, I took down their game logs for each season based on their age. The fantasy outputs were entered based on which game the team was playing during the season. If they were playing in Week 10, but they had already had their bye, that went down as Game 9.

Finally, for each age, I broke the game logs into three groups. Every five weeks, a new group began. This gave a larger sample size for each portion of the season for each age while still being able to accurately show whether or not the player's production declined as the year progressed.

In order to try not to muddle things, I only looked at the ages for which I had the data of at least 15 players. Otherwise, the sample sizes for the groupings of games would be too low from which to draw any actionable conclusions.

Do Older Running Backs Fall Off During the Season?

The table below shows the output of the data. The numbers on the top row indicate which range of games throughout the season are represented. The final game of the season was omitted as teams will often rest starters in that contest, and this would not be fully indicative of a true fall off as opposed to a mere coaching decision.

Again, the intent here isn't to see whether fantasy production declines as players age. By the end of the season, that drop off will be included into their pricing. Their in-season drop-off, however, may not.

When you look at the players in their age-29 and age-30 seasons, you see two different tales. The younger group had an up-tick in production over the final five fantasy-relevant games, while their senior counterparts were down from what they did in the first segment of the year. What can we take from that?

Because the decline that the players in their age-30 season saw wasn't overwhelming, I'd be willing to guess that this would end up largely being a wash over a large enough sample size. At most, it's not enough for me to definitively say that a running back in his age-30 season will produce less at the end of the year than at the beginning of the year. Sure, we did see a slight decrease, but I don't think it was an actionable one.

The same is true with age-29. Even though they saw their production go up, does that mean we should emphasize running backs who are exactly that age? I wouldn't think so. It is enough, though, to rule out a precipitous drop off at that time.

This, however, doesn't tell the whole story. Although the older running backs don't see much of a fall off, there still could be an opportunity cost if the younger running backs saw an increase. That does appear to be the case here.

Every grouping from age 22 to age 25 saw more production in the final five games of the season than they did in the first five games. Whether it be due to expanded roles in the offense or just not losing steam, these players went the opposite direction of what we'd expect for the older ones. That could be some actionable information.

Even if the older guys don't see a decrease in production, they also don't appear to see the same increase as the younger guys. Once expectations and salaries have been set through the first 10 games, one group of players may improve, leading to their being under-priced. The other group would be expected to merely maintain, which would make their prices be just about right.

This is an issue that boils down to opportunity cost. A player in his age-30 season may be priced appropriately, and you shouldn't expect him to see a decrease in his production. However, there may be pricing inefficiencies elsewhere. The presence of these inefficiencies would make that older running back less helpful to you as he would carry less value relative to his salary.

That's not to say you should simply stop using older running backs later in the season. Absolutely not. If they're in a good matchup or on a team that's heavily favored, that could give them a big enough increase to more than nullify the effects of old age. Yes, it's another factor to consider, but that doesn't mean that you should throw out the rest of your process completely.

If we were to try to make this more broad, it would seem that the players in their age-22 to age-25 seasons will see a slight increase over the final five games. We should give them a minor upward adjustment in our valuation as they may be priced below where their actual production will lie.

From age-26 to age-29, there doesn't appear to be much change at all. There were fluctuations, but there wasn't anything enough to sway me one way or another. You are likely safe keeping these players at the same valuation you had for them earlier in the season.

Once you get beyond that, it's more difficult to tell. There was a drop off for players in their age-30 season, but those in their age-31 season were relatively stagnant. I would -- at the very least -- be hesitant to use these players simply because they appear less reliable than their younger peers. I'm not ruling them out if things align well, but this is not something I would simply disregard.

Even though the grind of an NFL season may not be able to rival that in middle school four square, it does appear to have at least some effect on the production of running backs in daily fantasy football. The young guys don't appear to face any resistance in exceeding their early-season production, while the veterans remain equal or worse. Age isn't the most important factor to consider when filling out your lineups, but it should serve at least some sort of role within your process.