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The Dallas Morning News called me yesterday to see if I could help with their research on NFL punt trajectories. The obvious reason was because A.J. Trapasso hit the Dallas Cowboy’s center-field score board while punting.

In 2006, I wrote a blog post on this site about the optimum angle for kicking a punt. That is how the Dallas Morning News found me. I was putting together a paper (probably for the American Journal of Physics) based on that blog post, but I never finished. I have the original literature review, though, so finding the info that the newspaper wanted was pretty easy.

As I mention here, Peter Brancazio conducted a study in 1985 of 238 punts made by 24 different NFL punters. What he found is that punters typically don’t punt for maximum distance, but to balance distance with hang time. His study found that on average, NFL punters kick the ball at an angle of 57 degrees with an average speed of 60 mph. With these parameters, a NFL punt would have an average height of about 90 feet, which is exactly the hight off the ground of the Cowboy’s scoreboard. Air resistance would probably decrease this number 10-15%, though. More important, though, were parameters for “elite” kicks. An elite kicker can boot the ball with speeds up to 70 mph. At the same average angle, that results in a height over 120 feet.

The Dallas Morning News liked my analysis so much, that they quoted me in the article along with Tim Gay, author of the book “Football Physics”.

Tim Gay, author of Football Physics: The Science of the Game, said he spent several years researching his book and found little information about the height of punts.

Gay, a physics professor at the University of Nebraska, said that based on rough calculations, punts for the longest distance would probably go only about 60 feet above the field during a game that counts. Others that maximize hang time would be more likely to reach about 105 feet.

However, he said it’s unlikely that a player would kick a sky-high punt directly in the center of the field. Gay said such kicks would be more likely to be angled, and it would only take a 10 percent change in the angle to clear the video board.

Christopher Moore, a physics professor at Longwood University in Farmville, Va., said he would be concerned about the board. Based on other calculations, he estimated that elite punters could send the ball sailing 120 feet above the field – although that doesn’t take into account air resistance.

I’m not sure what data Dr. Gay used for his estimates, but I think he is estimating a little on the low side. I believe he is making his estimate based on maximizing the distance, which requires a 45 degree angle. In fact, this is the Cowboy’s punting game plan as stated by Matt McBriar in the article. However, many teams gameplan around hang time, rather than distance. You know the speed of your gunners, so the punter (in long field situations, which is exactly what we need to look at, here) will try to hang the ball in the air long enough for them to be staring down the punt returner before the ball is caught.

In fact, the data tells us exactly that. Again, the average angle for a punt in 1985 was found to be 57 degrees, not 45. In the range of booting ability for elite NFL punters, that scoreboard has the potential to be hit many times during the season.

It feels odd quoting a quote of myself, but I’m going to do it anyway:

“It’s not a matter of whether the board will be hit,” Moore wrote in an e-mail. “It already has been. What the physics suggests is that the board will be hit often.”

UPDATE: I just finished reading the chapter on kicking in Tim Gay’s book “Football Physics”. He references Brancazio’s study, too. From Brancazio’s data, though, he should be concerned, since it seems like there is maybe a 1 in 15-20 chance that the punter will hit the board during an average game. That’s somewhere in the neighborhood of every other game if opposing teams don’t change their kicking strategies. I sure do wish the NFL collected hang-time data for every kick.

UPDATE 2: I did an analysis with a literature-based estimate for drag coefficients, and my conclusion stands. A good kick in a game-day situation has the potential to hit the board. You may be able to see my analysis in February at the AAPT Winter Meeting. Stay tuned.