31 December 2017

Physics and Psychology Aid Callahan's Punt Return TD!

The Chicago Bears finished a rather dreadful season with a loss to the Minnesota Vikings today, 23-10.  The Bears did have a fun play that I got to analyze for TuneIn's Ho Huddle.  With just over six minutes left in the first half, the Vikings faced a 4th and 9 at their own 16-yard line.  Vikings' punter Ryan Quigley (#4) punted the ball from Minnesota's 7-yard line (click on image below for a larger view).
You can see in the above screen capture that Quigley was right on the 7-yard line when the ball left his right shoe.  The ball was punted at almost 60 mph and over 60 degrees to the horizontal.  For an incredibly short amount of time, the force between shoe and ball on a good punt can be over 1000 pounds.  The punted ball traveled 53 yards and had a hang time of 4.24 seconds.

The problem for the Vikings was that the Bears' Tarik Cohen (#29) played the perfect decoy.  He was on the right side of the field and acted as if he was going to catch Quigley's punt.  But Bryce Callahan (#37) was on the left side of the field and caught the punt while sliding on his own 40-yard line (click on image below for a larger view).
Look at Cohen with his arms out like he's about to catch the punt!  The Vikings' Jayron Kearse (#27) is running full speed at Cohen while Callahan has just caught the punt.  The screen capture below shows when Callahan got up after his slide (click on image for a larger view).
You can see the purple blurs heading toward Cohen!  I couldn't tell from the video I watched, but Quigley should have been yelling at his teammates, telling them where his punt was headed.  Even though the Vikings were at home, the noise level could have been in the 70 dB - 100 dB range, which corresponds to the sound a vacuum cleaner makes all the way up to what a busy subway sounds like.  Quigley's teammates down the field probably wouldn't have heard him if he was yelling.

Callahan could get up after his slide and run because the NFL doesn't use college football rules.  The screen capture below shows that Callahan had many blockers in front of him (click on image for a larger view).
The Vikings are headed to the right while Callahan is preparing to run down the left side of the field.  Cohen did such a good job selling the fake that Kearse nearly ran into Cohen and had to veer off to Cohen's left upon realizing that Cohen didn't have the ball.  Check out the screen capture below, which shows five Vikings near Cohen, all realizing too late that they ran after the wrong player (click on image for a larger view).
Meanwhile, Callahan was hitting a top speed of 19 mph in Vikings' territory (click on image below for a larger view).
Callahan crossed the goal line at about 16 mph, having slowed a little to celebrate (click on image below for a larger view).
A lot of great physics for sure, but psychology had the Vikings off course and chasing the wrong Bear!  The Bears finished 5-11 this year, but left me with a fun play to analyze before bringing their season to a close.

Chuck Nice of Playing with Science joined me on today's segment.  As he always does, Chuck set up the play really well before tossing it over to me for the nerdy stuff.  Click here for our segment.  The NFL regular season finished up today, but like the 13-3 Vikings, we football fans are anxious for the playoffs to begin!

28 December 2017

Extended Classic: The Science of "The Catch"

This past Wednesday night's episode of Playing with Science took another look at Odell Beckham Jr's famous one-handed catch.  Click on the link below to hear me discussing the physics behind the catch.

It's a great time of year to talk football physics!

24 December 2017

Gurley Outruns Titans!

The Los Angeles Rams edged the Tennessee Titans today, 27-23.  The Rams were helped in their efforts by an incredible run by Todd Gurley (#30) that took place with less than five minutes to go in the first half.  The Rams faced 2nd and 11 from their own 20-yard line.  Quarterback Jared Goff (#16) -- no relation! --was in the shotgun (click on image for a larger view).
You can see Gurley standing to the right of Goff.  I've also circled Johnathan Cyprien (#37), the strong safety for the Titans.  Cyprien was blitzing.  The screen capture below shows Cyprien's view of Goff before the play started (click on image for a larger view).
After Goff took the snap, he backpedaled to the Rams' 10-yard line before throwing a screen pass toward Gurley.  But Gurley was lucky to even receive the ball because Cyprien almost tipped Goff's pass.  Check out the screen capture below (click on image for a larger view).
I've cropped the original screen capture and blown up the image, which is why it's a little grainy.  Using a standard length measurement associated with Goff's height, I estimated that Cyprien's fingers missed the football by less than four inches.  Football really is a game of inches!

Gurley caught Goff's screen pass at the Rams' 15-yard line, which was 5 yards behind the line of scrimmage (click on image for a larger view).
Notice that Gurley is turning clockwise (as seen from above) in preparation for his run.  What got Gurley to the end zone 10.5 seconds later wasn't just the blockers in front of him.  The Rams benefited from Gurley's amazing speed.  Gurley simply outran all the Titans!  Not long after crossing midfield, Gurley hit a maximum speed of almost 22 mph (click on image for a larger view).
Look at those Tennessee defenders trying to catch Gurley!  To put his 22-mph speed into perspective, consider Usain Bolt.  At the peak of his sprinting powers, Bolt exceeded 27 mph.  But he wasn't wearing pads and a helmet that total almost 20 pounds!

Check out Gurley scoring below (click on image for a larger view).
Fast-twitching muscles and blinding speed on the part of Todd Gurley allowed Jared Goff to throw a football 5 yards and get credited for an 80-yard touchdown pass.  How great is that?

I tracked where Gurley was as he passed each yard line.  I then determined his velocity component in the direction perpendicular to the yard lines.  The plot below shows Gurley's run just after he caught the ball and got going (click on image for a larger view).
Gurley ran most of those 85 yards along the left hash marks.  Just before reaching the Titans' 15-yard line, he ran toward his right to avoid tacklers.  His speed dropped as he neared the goal line, but not quite as much as the above graph indicates.  By running toward his right, Gurley added to his velocity a component parallel to the yard lines.

Chuck Nice of Playing with Science joined me on TuneIn's No Huddle to chat about Gurley's magnificent run.  Click here for our segment.

20 December 2017

Extended Classic: The Immaculate Reception

Tonight's episode of Playing with Science revisits the Immaculate Reception, which was a famous catch (or not?!?) by Franco Harris of the Pittsburgh Steelers during the 1972 NFL playoffs.  Click on the link below to hear me and others talking football physics.
 It's always fun talking sports physics, especially physics on the gridiron!

17 December 2017

A Bullet from Keenum to Diggs!

The Minnesota Vikings obliterated the hapless Cincinnati Bengals today, 34-7.  With less than seven minutes to go in the second quarter, Case Keenum (#7) fired a bullet to Stefon Diggs (#14) that pushed the Vikings lead to 23-0, but Diggs took a couple mighty hits after scoring.  Check out the Vikings' shotgun formation on 2nd and 16 from the Bengals' 20-yard line (click on image for a larger view).
Note Cincinnati cornerback Tony McRae (#29) covering Diggs.  Another look at the formation shows the one Bengal on defense that you can't see in the above screen capture.  Check out the view from behind Keenum (click on image for a larger view).
Standing just inside the Bengals' 5-yard line is free safety Clayton Fejedelem (#42).  McRae and Fejedelem were about to become the bread in a Stefon Diggs sandwich!

Keenum took 2.24 s from the snap to throw his pass.  The Bengals rushed four, but the Vikings had five offensive lineman in pass protection.  Keenum threw the ball from the Bengals' 27-yard line while inside a perfect pocket (click on image for a larger view).
That's some great blocking for Keenum!  Diggs was running a post route and Keenum fired the ball at 50.1 mph at 15.8 degrees above the horizontal.  The ball reached Diggs 1.30 s later at 46.4 mph.  Air drag was about 17% of the ball's weight just after Keenum released the ball.  The plot below shows the trajectory of Keenum's pass (click on image for a larger view).
Diggs was running about 16 mph when he caught the ball at the goal line (click on image for a larger view).
But notice what was about to happen to Diggs.  Immediately after crossing the goal line, Diggs was met on his left by Fejedelem and on his right by McRae.  The two Bengals crunched Diggs a couple yards into the end zone.  Fejedelem hit Diggs with an average force in excess of 500 pounds, and that was very quickly followed by a hit from McRae with a similar force.  Look at the start of the hits (click on image for a larger view).
From another view, you can see what that 500-pound hit by Fejedelem looked like (click on image for a larger view).
Now look at the next screen capture as McRae gets his hit on Diggs (click on image for a larger view).
What's incredibly lucky for Diggs is that he was ever-so-slightly ahead of the two Bengals' defenders.  The last image I'll show you of the hits demonstrates that fact, but still makes it clear that football collisions are violent (click on image for a larger view).
Diggs surely thought a little pain was worth the score!  Had he not been a tiny bit ahead of his tacklers, he might have felt forces greater than 1000 pounds during a very short time interval.  Don't forget Newton's third law though, though.  The two players who tackled Diggs felt equal-magnitude forces from Diggs.

After Diggs got up from the two big hits he took, he celebrated by going to the back of the end zone and fired the ball into the purple padding behind the end zone.  He actually threw the ball at about 41 mph, which wasn't that much slower than the pass he had just caught from Keenum!  Check out Diggs throwing the ball (click on image for a larger view).
Gary O'Reilly of Playing with Science joined me on TuneIn's No Huddle to discuss the play.  As always, Gary did a great job setting the play up before I threw some physics into the discussion.  Gary noted that if Diggs doesn't spike the ball when he scores, watch out for his throw!  Click here for our segment.

10 December 2017

Snow Physics Helps the Bills!

Who doesn't love playing football in the snow?  If you get lucky and have some snow on Thanksgiving, you go all out in the Turkey Bowl, diving for catches and sliding in the snow.  How great is it that professional football keeps being played whether it's raining, windy, or snowing?  The Indianapolis Colts visited the Buffalo Bills today and were treated to wind and snow.  The Bills won in overtime, 13-7, in a game in which snow physics played a major role.

Scoreless near the end of the first half, the Bills had 1st and goal at the Colts 8 yard line.  Check out the formation below (click on image for a larger view).
I've circled four key players in the above screen capture.  Look at that field and note that the image isn't crisp because it was snowing at the time.  Players in snow can lose about 30% of the friction on their shoes from what they're used to.  They can't run with long strides or they risk slipping.  A football brought from a warm locker room can lose a couple psi because air molecules aren't bouncing around inside the ball as much as they were in the locker room.  The air temperature in Buffalo at the time of the above play was about 30 F.  Air at that temperature is about 9% denser than air in a balmy 75-F stadium, and that added air density makes for more air resistance on passes.

Snow physics helped the Bills score from the formation shown above.  The Colts rushed just four, but there is a reason I circled left defensive end, Margus Hunt (#92) in the above image.  Check out the image below, which is 2.6 s after the above image (click on image for a larger view).
Margus Hunt slipped and fell forward in the snow!  All of a sudden, the right side of the Bills line had no rush to block and there was no defender on that side to swat the pass.  By the time Hunt got up, it was too late.  The screen capture below shows Bills quarterback Nathan Peterman (#2) releasing his pass at 45 mph and 21 degrees above the horizontal (click on image for a larger view).
The ball was released outside the Colts 10 yard line.  Bills wide receiver Kelvin Benjamin (#13) only reached 11 mph prior to crossing the goal line.  He caught the pass 1.43 s after Peterman released the ball (click on image for a larger view).
Note Colts cornerback Christopher Milton (#28) looking over his left shoulder.  He had gotten turned around in the snow and didn't have enough shoe friction in the snow to close the gap and stop Benjamin from making the catch.  Benjamin caught the pass while it was moving at about 41 mph.  Benjamin's padded gloves increased friction with the ball so that he could secure the catch in the snow.  Check out his perfect two-handed catch below (click on image for a larger view).
Milton certainly had a great view of Benjamin's catch!  Credit Benjamin for superb fundamentals.  Though Benjamin couldn't reach his top speed while running with short strides in the snow, slippery snow physics hurt the Colts' defense!

The trajectory of Peterman's pass is shown below (click on image for a larger view).

The ball only got about 5 yards above the snow on its flight to Benjamin's gloves.  But that was all the height needed for a pass thrown at the 11 yard line and caught halfway into the end zone near the right sideline.

Chuck Nice of Playing with Science joined me on TuneIn's No Huddle to discuss some snow physics and the above play.  Chuck was great setting up the play and then I rambled about the physics.  Click here for our segment.  We got a little snow in Lynchburg yesterday, but I'm jealous of all the snow in Buffalo!

03 December 2017

Tarik Cohen's INSANE Punt Return

The Chicago Bears lost a nail-biter to the Francisco 49ers today, 15-14.  But the Bears didn't disappoint as football fans were treated to an incredible punt return in the second quarter.  San Francisco's Bradley Pinion (#5) received the snap and launched his punt at about the 49ers 7-yard line (click on the image for a larger view).
Pinion's punt traveled about 54 yards in the air with a hang time of 4.2 s.  That's a typical hang time and should have given the 49ers plenty of time to get downfield to defend against the punt return.  But their defense looked more like a Tour de France peloton than proper football pursuit!

Chicago's Tarik Cohen (#29) fielded the ball at the Bears 39-yard line (click on the image for a larger view).

Note that Cohen caught the punt just to the left of the painted 40 on the field.  Chaos ensued after Cohen's catch!  He first noticed two 49ers about 8 yards in front of him.  He then ran backwards and to his right.  Check out the screen capture below, which is 2 s after Cohen caught the punt (click on image for a larger view).
San Francisco's Aldrick Robinson (#19) had both his hands on Cohen!  But Cohen kept running backwards.  Check out the 49ers pursuit when Cohen got to the other side of the field (click on image for a larger view).
There are SEVEN 49ers running after Cohen with no blockers in their way!  The problem is that they all ran as one.  Instead of fanning out and covering more of the field, they looked like a cycling peloton or a flock of birds changing directions.

Cohen ran back across the field to nearly the spot where he caught the punt.  His teardrop-shaped path backwards towards the other side of the field took 8 s off the clock!  He then hit his own 40-yard line and turned on the jets.  He sprinted 50 yards, hitting a top speed of just over 20 mph.  Slowing to 15 mph for the final 10 yards, Cohen crossed the goal line nearly 15 s after he caught the punt! (click on image for a larger view)
Though he was credited with a 61-yard punt return, Cohen ran about 119 yards in total!  That was nearly TWICE was he was credited for!  He also had to catch the punt while staring into the sun.  That was one amazing punt return!

Gary O'Reilly of Playing with Science joined me on TuneIn's No Huddle to discuss this play.  Gary did a great job setting up the play and then I yapped some physics.  Click here for our segment.  A fun play to analyze!