Making Sport of Physics

From Saints Sandwich to Touchdown!

No Huddle asked me to analyze a nice touchdown thrown by Washington Redskins’ quarterback Kirk Cousins to Ryan Grant.  Unfortunately for the Redskins, the New Orleans Saints had a monster 4th-quarter comeback and won the game in overtime.

The play I analyzed took place late in the 3rd quarter with the shot clock winding down.  The Redskins faced a 3rd and 7 from the Saints 40-yard line.  Cousins (#8) was in the shotgun and just prior to the snap, the Saints sent both safeties in for a blitz into the middle of the Redskins’ line.  Washington had seven blockers, including running back Samaje Perine (#32).  But the Saints had eight rushing the quarterback and it doesn’t take a rocket scientist to know that 8 is greater than 7.  Kirk Cousins was about to get smashed!

The Saints’ safeties had a running start on the blitz.  Cousins received the ball 0.43 s after it was snapped and the hungry Saints defenders were rushing for the sack.  Ryan Grant (#14) was on the right side of the Washington formation.  Check out the start of the play below from the screen capture I took (click on image for a larger view).

Grant sprinted to the right sideline as Cousins held the ball long enough for Grant to get open.  The left side of the Redskins’ line broke down and Cousins was going to be blindsided by defensive end Alex Okafor (#57).  Cousins had taken four big steps back and threw the ball a full 2 s after he received the snap.  Just as he threw, he became the meat in a Saints sandwich as he got crushed by Okafor and safety Vonn Bell (#48).  Safety Rafael Bush (#25) piled on after the initial hit for added damage.  Check out the carnage below (click on image for a larger view).

Not much fun for Cousins, was it?  But he got the ball where it needed to be!  Cousins released a great spiral into low-Earth orbit at the speed of 46 mph at 30.7 degrees above the horizontal.  The ball traveled just over 38 yards in total horizontal distance, reaching a maximum height of about 8 yards above the turf, and took 2.1 s to reach Grant.  It landed in his hands at about 41.6 mph.  An air resistance force of about 15% of the ball’s weight was acting on the ball while in flight.  Check out the graph below of the ball’s trajectory (click on image for a larger view).

Grant had run past two unsuspecting Saints defenders and was wide open for the catch.  Check out just how open he was (click on image for a larger view).

Where was the defense?!?  All that was left for Grant was a stroll into the end zone with perhaps a little taunting thrown in.  After scoring, he tossed the ball into yet another low-Earth orbit.

For the audio on TuneIn Radio, click here.  Gary O’Reilly of Playing with Science joined me on the show and did a wonderful job setting up the play.  During my analysis of the play, I was interviewed by Alissa Smith of the Lynchburg News & Advance.  Gary O’Reilly was kind enough to give Alissa a few comments for her story.  Click here for the story that appeared in the Monday, 20 November 2017 edition of the paper.

Posted in Uncategorized

A Great Fake Punt!

For this week’s appearance on TuneIn Radio, I got to discuss a great fake punt in the Jacksonville Jaguars’ overtime win against the Los Angeles Chargers.  At the end of the first quarter with no score, the Jaguars were lined up for a punt.  It was 4th and 7 on their own 44-yard line.  Brad Nortman was set to receive the snap from long snapper Matt Overton.  Corey Grant was behind the Jaguars’ line to the right of Overton.  Check out the screen capture I got of the formation below (click on the image for a larger view).

I circled Nortman, Grant, and Paul Posluszny, who followed my yellow arrow into an incredible block.  Nobody was lined up across from Overton, and thus a lineman didn’t notice that Overton was ever-so-slightly angled toward Nortman’s right.  He would direct snap the ball to Grant.  Check out the hole that the Jaguars’ line opened up for Grant, and note Posluszny’s great block to seal the side of the hole to Grant’s right (click on the image for a larger view).

Notice Grant is headed toward the massive hole as Posluszny runs right in front of him.  Grant had faked to his right to give Posluszny time to get in the hole for the seal block.  Nortman rolled out to his left to help sell the fake.

The Chargers had two shots at stopping Grant.  The first was by #40, Chris McCain.  Grant stiff-armed McCain at the Jacksonville 45-yard line as McCain dove toward Grant.  The problem with McCain’s tackle attempt is that McCain’s force mostly pulled downward on Grant’s legs.  That wasn’t going to alter Grant’s forward linear momentum!  Check out the screen capture below (click on the image for a larger view).

McCain tried for Grant’s feet, but Grant stabilized himself just a like a tightrope walker does.  Notice both his arms are extended outward.  That makes it harder to move Grant’s center of mass outside his shoes, which would cause a gravitational torque to make him fall.

The second and last hope for the Chargers was #20, Desmond King.  He had an open-field shot at Grant near the Los Angeles 42-yard line.  But once Grant spied King, Grant shot to his left.  When King drove for Grant, Grant hurdled over nine feet horizontally to avoid having his legs taken out.  Look at Grant’s athleticism below (click image for a larger view).

King dove, but Grant leapt to daylight.  Once Grant cut hard to his right at the Los Angeles 35-yard line, he outran the defense to the goal line.  Those hard cuts can lead to well over 100 pounds of force on a running back’s legs.  It’s no wonder the average career length for an NFL running back is only about four years!

What I especially love about the play is that it took nearly 11 seconds to complete.  Someone could have jogged 10.6 mph along the sideline at the snap of the ball and gone 56 yards to the goal line in the time it took Grant to score.  Grant was through the initial hole at 15 mph, and then hit a maximum speed of about 19 mph halfway into Los Angeles territory before scoring at nearly 18 mph.  A sideline jogger that went 56 yards would have watched Grant run a total of about 85 yards!

Chuck Nice of Playing with Science joined me on today’s radio segment.  Chuck did a great job setting up the play and then I yapped some physics.  Click here for our segment on TuneIn’s No Huddle.  It was a lot of fun talking football physics!

Posted in Uncategorized

Return from Kenyon College

I returned from my visit to Kenyon College today.  Friends and colleagues know why the trip was difficult for me.  Kenyon College has been a special place for me since 1999.  Unfortunately it now represents a place of broken promises and betrayal.  What helped me considerably was the warm reception I received upon meeting up with former colleagues.  It was great chatting with old friends again.  I also enjoyed meeting new people and spending a few minutes discussing my research with Kenyon’s bright physics majors.  I had fun giving my talk.  The photo below shows me a couple minutes before my talk began (click on the image for a larger view).  Pizza helped attract a few extra students!

The chalkboard shows some belated Halloween math I used to entertain people before I got introduced.  Nothing like a little mathematical nonsense to lighten an audience!

Posted in Uncategorized

Talk at Kenyon College this Friday

I will return this Friday to where my post-doctoral career began, Kenyon College in Gambier, Ohio.  There are many reasons why I look forward to being back at Kenyon, but there are several personal reasons why the trip will be difficult for me.  I’ll do my best to put those reasons aside and have a great trip to a place that still means a lot to me.  I certainly look forward to discussing three of my research areas with the good people at Kenyon.  Either click here or on the poster below for information about my Friday talk.

Posted in Uncategorized

Great Blocking for a Great Touchdown!

The Philadelphia Eagles rolled over the Denver Broncos yesterday to the tune of 51-23.  Gary O’Reilly and I represented Playing with Science on yesterday’s No Huddle segment on TuneIn, during which I analyzed Jay Ajayi‘s impressive 46-yard touchdown run in the second quarter.  Click here for the No Huddle segment.

Ajayi’s touchdown run was so fun to analyze that I decided to write a bit more in my blog post.  Linear momentum, forces, and the laws of physics played crucial roles in the touchdown, like they do in most everything else that happens in the world.  Look at the screen capture below for the start of the play (click on the image for a larger view).

The Eagles have 1st and 10 at the Broncos’ 46-yard line.  Quarterback Carson Wentz is in the shotgun and Ajayi is lined up on Wentz’s right.  Note there are four defensive lineman and five offensive lineman.  Eagles’ center Jason Kelce is not lined up against anyone.  Kelce is about to play a major role in the play with some key blocking.  Before that, he had to snap the ball to Wentz.  The ball took about 0.4 s to reach Wentz, which is about the time it takes for a major-league fastball to reach home plate.  Once he snapped the ball, Kelce pulled to his left, Ajayi took two strides to his left to receive the ball from Wentz, and then he witnessed the most beautiful blocking open up before him.  Check out the blocking in the image below (click on the image for a larger view).

Eagles’ left tackle Halapoulivaati Vaitai had Broncos’ outside linebacker Shane Ray (#56) blocked.  See the yellow circle in the above screen capture.  Eagles’ left guard Stefen Wisniewski had Bronco’s defensive end Shelby Harris taken care of.  See the orange circle in the above image.  Look at the hole Ajayi is about to run through!  After getting the ball from Wentz, Ajayi needed just five strides to get to the hole.  Note the white arrow on lead blocker in the hole, center Jason Kelce.  He has his eyes on Broncos’ strong safety Justin Simmons.  Take a look at the blocking scheme from another view (click on the image below for a larger view).

That’s quite a hole, right?  The Eagles’ lineman employed their intuitive physics knowledge of linear momentum to set up the great run.  Isaac Newton taught us that a net, external force is needed to change an object’s linear momentum.  The product of an object’s mass times its velocity is an object’s linear momentum.  Beefy lineman have lots of mass and thus need lots of force to stop.  A couple hundred pounds of force to stop a defensive lineman are not out of the ordinary.  Offensive lineman intuitively know that linear momentum and force are vectors, which means they have directions as well as magnitudes.  Keep that in mind for the end of the play.

The great line blocking allowed Ajayi to hit the hole at a speed of about 19 mph (31 kph).  He was able to maintain that speed while running down the left sideline.  While running toward the goal line, Ajayi’s linear momentum was pointed right at the goal line.  Broncos’ free safety Darian Stewart was Denver’s last hope on the play.  Unfortunately for Stewart and Denver, linear momentum was working against them.  Check out the screen capture below as Stewart hit Ajayi at the Broncos’ 3-yard line, just below Ajayi’s hip (click on the image for a larger view).

Stewart hit Ajayi with a force nearly perpendicular to Ajayi’s linear momentum.  That certainly changed Ajayi’s linear momentum, but mostly perpendicular to the left sideline.  Despite a force of several hundred pounds over less than 0.1 s, Ajayi’s linear momentum change was mostly toward the out-of-bounds area.  That works great unless an athlete like Jay Ajayi is a couple yards from glory and he is able to contort his body.  He still had much of his linear momentum that was pointed toward the goal line after the hit.

Just as he was hit, Ajayi rotated toward his right.  That ensured that after he was hit, his ball-carrying left arm would be above his body and ready to pass over the orange pylon for a touchdown.  See what I mean in the screen capture below (click on the image for a larger view).

From the terrific blocking at the start of the play to Ajayi’s contorted body over the pylon, linear momentum was the 12th man on the field for the Eagles!

Posted in Uncategorized

Fun Chatting World Series!

Last night’s episode of StarTalk‘s Playing with Science focused on the World Series.  We discussed many iconic moments, such as Willie Mays’ famous over-the-shoulder catch in the 1954 World Series and Kirk Gibson’s lone at-bat in the 1988 World Series.  Click below for a link to the episode.

The above episode aired a week earlier only on TuneIn.  Click here for that link.
Last night the Astros evened up this year’s Fall Classic with a thrilling 11-inning win.  Game 3 will be in Houston tomorrow night.  I love baseball and I love the World Series, but I grew up with the Astros in the National League.  This year’s World Series has a weird feel for me!
Posted in Uncategorized

Great pick by Eddie Jackson!

I had a lot of fun analyzing Eddie Jackson‘s second interception in yesterday’s Bears’ win over the Panthers.  Jackson, a rookie safety out of Alabama, perfectly timed his run to a tipped ball and took Cam Newton’s pass 76 yards for his second TD.  His first came on a 75-yard interception, meaning Jackson became the first defensive player in NFL history to have two 75+-yard returns for touchdown in one game.  Check out my screen capture below as Jackson just gets to the deflected pass (click on the image for a larger view).

Can you tell which player is moving fastest?  It should be obvious by the amount of blur!  The Panthers’ Kelvin Benjamin was the intended receiver.  He appears to have a good bead on the ball after Prince Amukamara got his right arm on Benjamin’s chest just as Newton’s pass arrived.  But that blur coming from the right is Eddie Jackson, moving at nearly 17 mph.  That running start was all he needed to snag the ball and take off for a pick six.  I’m sure the fact that Cam Newton went to Auburn made the interception all the sweater!

The above play is the one I discussed on TuneIn yesterday.  Gary O’Reilly joined me as we pitched the wonders of Playing with Science.  Click here for our segment on yesterday’s No Huddle.

Posted in Uncategorized

NFL Physics

Chuck Nice, Gary O’Reilly, and I joined Brian Webber and Nick Ferguson on TuneIn‘s 1st & Goal this past Sunday.  We discussed Golden Tate‘s great touchdown run during Detroit’s loss to New Orleans.  There was some terrible tackling during the play, but Tate capped his touchdown run with a spectacular front flip into the end zone.  Check out the screen capture I took of Tate crossing the goal plane (click on the image for a larger view).

I analyzed the play and provided physics commentary.  As he crossed the goal plane upside down, Tate was moving 12 mph and rotating at 60 rpm.  Think you could score a touchdown like that?!?

Click here for the seven-minute segment that contains more of my physics analysis of the Tate’s touchdown.  It was a lot of fun doing a live show!

Posted in Uncategorized

StarTalk’s Playing with Science

I meant to write a blog post about my appearances on StarTalk‘s Playing with Science, but my life, both professional and personal, has kept me extremely busy in recent months.  Appearing on the show and talking about sports physics has been a lot of fun!  Chuck Nice and Gary O’Reilly are great hosts of the show and I always enjoy my interactions with them.  Below is a list of the episodes I’ve appeared on.  Click on the links to access the episodes.

Check out all the other great episodes with fascinating guests from the world of sports and science by clicking on the image below.


Posted in Uncategorized

Froome Wins 4th and We’re Nearly Perfect!

After his performance in the Alps and in yesterday’s time trial, there was no doubt that Chris Froome would win his fourth Tour de France.  He now has a three-peat (should I send Pat Riley money for using that term???).  Froome didn’t win a stage this year, but was clearly the best cyclist.  Staying near the winners in the mountains and in the time trials, Froome was simply better than everyone else.  His Team Sky mates played a large role in his victory.  It doesn’t hurt to be supported by a powerful team!

Dutch cyclist Dylan Groenewegen won today’s final stage.  How did our model perform today?  We saved our best for last, as you’ll see below.

  • Stage 21:  2h 25′ 39″ (actual), 2h 25′ 50″ (prediction), 00′ 11″ slow (0.13% error) 

As tough as it is to predict the mostly-ceremonial final stage, I’m thrilled to end this year’s Tour de France with a near-perfect prediction.  How did our model perform overall?  After summing the stage-winning times, I found we were 1.11% slow.  I’ll definitely need to spend time thinking about how much athletes and technology have improved since last year.

I never cease to be amazed by elite athletes.  A total of 167 cyclists finished the Tour de France.  I would be hard-pressed to finish a long flat stage during daylight hours.  As for those grueling mountain stages, forget it.  I need more time in the gym!  My model estimates energy burn, i.e. internal energy burn with an average efficiency of about 20% and not just energy output needed to power the bike.  During the entire race about 115,000 Calories could have been burned.  Published cyclists’ data may be below that number, but an estimate has to be made of internal energy efficiency.  Our published papers on Tour de France modeling cite sources that are consistent with our energy estimates.  The point is that a LOT of energy is burned during the three-week race.  At 550 Calories apiece, those 115,000 Calories amount to nearly 210 Big Macs.  That averages to 10 Big Macs per stage!  I don’t recommend eating Big Macs before cycling, but it does give you some idea of how much energy those cyclists burn each day.  You may have heard that 3500 Calories matches the energy content in a pound of fat.  That’s roughly true, but you may have to burn about twice the Calories to get a pound of fat off because of the complicated way the body converts energy.  Either way you think about it, 115,000 Calories represent one or two bowling balls of fat weight.  No wonder elite cyclists stay in such great shape.  Their job is a wonderful form of exercise!

I once again thank rising high-school senior Ryan Wainer from New York for his work this year.  He acquired all the terrain data, which led to a successful set of predictions.  How successful?  We had one bad prediction with Stage 5 (9.24% error) and five good-a-decade-ago-but-want-to-do-better-today predictions in the error range of 4% – 8%.  But that leaves 15 predictions to better than 4%, 11 of which were better than 2%.  Five of those 11 were better than 1%, including our best prediction today.  A nice way to end!

Posted in Uncategorized