If you are pulling this information, then I'd also pull the teams rushing yards or just their runningbacks yards, or yards per carry...or whatever performance metric you want to use.

Then take the ages of the lineman and do a simple correlation analysis to see if across the NCAA there is a strong positive correlation between age and yards. This is leaving out a lot of potentially confounding variables, but it is a pretty good starting point to actually see if there is ANY validity to the argument.