Writers of Pro Football Prospectus 2008

05 Apr 2011

ESPN: Pro Day 40s

This week's ESPN Insider feature looks at the 40-yard dash times of players who run at both the Combine and at Pro Days to note how "field effects" likely exist for different schools.

Posted by: Bill Barnwell on 05 Apr 2011

7 comments, Last at 08 Apr 2011, 4:22pm by AlanSP

Comments

1
by mkuske (not verified) :: Tue, 04/05/2011 - 3:33pm

I read your take on pro day 40s vs. combine 40s and it took me back to something I thought I had noticed before...that combine times seem to have been slower since the move to Lucas Oil. What I would like to see is how the times at Lucas Oil match up to the times at the RCA Dome.

I know you couldn't compare times up for a single player, but it would be interesting to see the average or median 40 times for position groups before and after the move. Maybe knock out the top 3 and the bottom 3 and average the rest. Also, what part of the 71% who improved their time at their pro day happened prior to the move and what part after the move? Just curious.

6
by Jimmy :: Wed, 04/06/2011 - 6:16pm

I reckon that the difference between the two surfaces is .05 to .08 of a second. The really messed up thing is that there must be a physical reason why the times are slower so the turf must have more give in it, or whatever it is that makes some fields slower than others. Similar to how racehorses with different running actions will perform differently on firm to soft footing the same must to an extent be true of people. So the combine gives you a time for a player running in shorts on a surface that may or may not suit his running style. The player will also not have played a football game for a couple of months and have spent the intervening time learning to do sprint drills instead, not exactly the same as preparation for an NFL game. The more you think about the odd parameters and variables of guys running 40s at the combine (or a pro day) the more I think that if I were a talent evaluator I would rather watch more tape than pay it much mind.

2
by cisforcookie (not verified) :: Tue, 04/05/2011 - 4:18pm

[i haven't read this article because i haven't got insider]

shouldn't we expect _all_ pro day numbers to be better than combine numbers? if a player likes his combine numbers, i imagine he wouldn't run/jump/lift/etc at his school's pro day. how could you separate having a better day from having a better track?

3
by Joseph :: Tue, 04/05/2011 - 5:16pm

I'd be interested to know how many guys run both, just the Combine, or just the Pro Day (prob. the biggest group).
I'd also expect some of these results; for example, any player who had an injury in his bowl game would be in better shape.

4
by Samson151 :: Tue, 04/05/2011 - 9:17pm

It ain't just home field vs away -- if you've been to the Combine, you know it's set up to irritate people. There's the cattle call aspect, plus having to perform at odd times, between other events, and often without the usual warm-up. Easy to see how that could produce mediocre performances. Maybe it's supposed to be a stress test. Prep for training camp.

5
by Aaron Brooks' Good Twin (not verified) :: Wed, 04/06/2011 - 12:01pm

Has anyone tracked 40 times over the years?

7
by AlanSP :: Fri, 04/08/2011 - 4:22pm

cisforcookie raises a good point above. There's definitely a selection bias in that players who did well at the combine are much less likely to want a do-over. So even if conditions at pro days were completely identical to those at the combine, you'd still expect more than 50% of the group who participate in both to do better at the pro day.

Maybe you could get an idea of this effect by looking at something unlikely to be affected by the conditions, like say bench press reps (not an exceptionally useful measure, but definitely the one least likely to be affected by conditions).

Unfortunately, that's sort of an apple/oranges comparison if you want to look at the amount of change from combine to pro day, but it could be viable if you just look at the percentage who perform better or worse. If, say, 60% do better on the bench press, you could treat that as a baseline level of improvement you'd expect from factors other than the conditions.