How pro days impact 40 times

Mark Ingram ran a disappointing 40-yard dash at this year's NFL combine. Joe Robbins/Getty Images

For prospects who struggled to put up a good 40-yard dash time at the NFL combine in Indianapolis, there's a second chance: pro days. Just about every major school in the country runs one for its graduating players, who get a scot-free opportunity to improve upon their times and scores from the scouting combine. Perform better, and you can talk about how you were nervous or had a slight injury in Indy; perform worse, and you can point to your combine numbers as the true measure of your athletic ability heading into the draft.

In reality, more than 71 percent of players from 2005 to 2010 put up 40 times on their pro day that were quicker than their same figures at the combine, and it's for two key reasons. First, modern players with serious NFL aspirations undergo training specifically designed to increase their 40. Since pro day events come weeks after the combine, that allows for more time to train. It's the second difference, though, that stands out as very interesting for fans of a particular school.

At the combine, every player runs the 40 inside the same dome, at the same spot, on the same turf. It's like the SAT: Because everybody takes the same test at the same time, it ends up being a reasonably fair measure of a player's athletic ability relative to other players who attended the same combine. At pro days, though, the conditions vary significantly. Consider that Penn State runs its pro day inside its practice facility on FieldTurf, while Florida State runs its pro day outside, where its artificial turf can be affected by wind or moisture. Some players run in track shoes with their shirts off; others run in football cleats with more clothing on. The timing is unofficial, with different scouts and agencies recording different results. If the combine is the SAT, judging players by their performance at pro day events is like comparing two college applicants by looking at the scores on their respective math finals.

And as it turns out, players at some schools are far more likely to dramatically improve their 40 at their pro day than those at other schools.