As the New England Patriots and the Los Angeles Rams head to the Super Bowl, a physicist and an athletic trainer sat down to talk about the physics of the game and the science of concussions.
This is the first episode of A Smarter U, a University of Lynchburg podcast featuring University of Lynchburg professors talking about current events and other items of interest.
Episode 1 features Dr. John Eric Goff, a well known sports physicist who has provided commentary in podcasts, articles, and TV appearances around the world, and Dr. Tom Bowman, an athletic training professor who is working on a National Football League-funded study on concussion treatment. Justin Cummings ’19, a communication studies major working for University Communications and Marketing, hosted and produced the episode.
Transcript: A Smarter U, Episode 1
Transcript prepared by Annabelle Nagy ’22
Justin Cummings – Welcome to a smarter you, a University of Lynchburg podcast! With the Super Bowl right around the corner, today we will be discussing football from a different point of view. I’m Justin Cummings and today I am joined by professor of physics, Eric Goff.
Eric Goff – Hey Justin. How are you?
Justin – And professor of athletic training, Dr. Tom Bowman.
Tom Bowman – Hey Justin. Thanks for having me.
Justin – Thank you guys for being here today. So, the Super Bowl has officially been set with the Rams and the Patriots. So, before we get into that, before we get into the Super Bowl itself, how has your research crossed paths with football and what led you to look at that specifically?
Eric – So, this is Eric here, and I have done a lot of research with soccer balls, which the rest of the world calls football. And I have always examined the World Cup footballs for the last dozen or so years and the interest with football came about two and a half years ago when StarTalk launched “Playing with Science” and I’ve been on that show ever since the very beginning and we’ve done all kinds of different sports from skating to baseball to Tour de France, soccer, and we’ve even done golf and football. And then two years ago partnering with “Playing with Science,” “Tune In” and the NFL had me start appearing regularly on Sundays to do play analysis. So, for the past two seasons I’ve been analyzing a play from the NFL, pulling out the physics and doing some calculations. Trying to elucidate what’s going on in the field in some of the more fascinating plays from the NFL in the past two seasons.
Justin – Awesome. Tom, what about you?
Tom – So, the majority of my work is focused on the sport of men’s lacrosse because we don’t sponsor football here at the University. When we do work in lacrosse, we always find ourselves comparing to football because, although lacrosse is the fastest growing sport in the world, football is king in America and that is probably the most popular sport. So, I’ve done some work on how to impact biomechanics with looking at what do head impacts look and feel like when our lacrosse and soccer players are on the field and we’ve compared those to some of the findings in football. And, I’ve also looked at protective equipment, looking at what makes a helmet good. And comparing football to lacrosse to hockey helmets and that sort of thing.
Justin – Awesome. We’re going to get back to helmets a little bit later. Let’s start with the physics side. So, Eric, why look at football physics? That’s something, as you said, you’ve been asked to do by the NFL for two seasons now, why does it actually matter the physics of a play?
Eric – Well, my interest has always been getting a little bit of science on the sports pages. I always like to try to get someone who is maybe not interested in science that often but who checks out the sports to maybe get a different look at it, so the eyes of a physicist looking at a football game. The laws of physics are obeyed by all of us. There are no exceptions in a football game even though some of the feats look rather spectacular. So, I think what surprises some of the people who hear the work of what is being put together and putting out each week for the season is just how large some of the forces are and some of the torques, collision times, and some of the things that people don’t really have to think about and when you tell someone that a football is spinning at 600 rpms that’s a little bit of a shock to them.
Justin – So, you said you do talk about a different play every week, you’re looking at a lot of these. So, from this season in particular, what’s one play that you found kind of the most interesting or exciting that you were like, “I can’t wait to talk about this.”
Eric – Well, one of the New England Patriots game when they were playing the Chicago Bears, and they beat them 38-31 in October, I really loved a play where the Bears had 3rd and 6 on the Patriots on the 8 yard line, so they really pushed a scoring. And the Bears Quarterback, Mitch Trubisky, a really fun guy to watch, he gets in the shotgun and as soon as the ball is snapped to him, he ends up holding the ball for about 12 seconds and then he runs a total of, what I calculated to be 72 yards on the play before he scored. So, that little 8 yards from the end zone turned out to be a 72 yard scramble to get into the end zone and score a touchdown. So, going through all of that and calculating step counts and speeds and all that to really analyze that play was a lot of fun. Maybe a little bit sadder play was when the Bears lost in the NFC wildcard playoff game to the Philadelphia Eagles. The very end of the game you had Cody Parkey, who was the kicker, come in for a 43 yard field goal and upon closer review, was a very slight finger tip touch on the ball that didn’t alter the trajectory very much but it hits the left upright and I thought an interesting thing to look at was if the ball is traveling to the north, I wanted to see how much the rotation of the earth was going to influence that trajectory and it turns out that the trajectory was actually given a little bit of a bump to the right, about a tenth of an inch. That wasn’t nearly enough to help the ball go through the upright, so even the earth turning didn’t help that field goal try.
Justin – So, like even a fingertip on the ball can really change something?
Eric – Oh sure, in that particular case the deviation was very, very tiny but sometimes that’s all it takes, in a game of inches.
Justin – That’s insane to me that just a single, you know, we look at football and we see it from a bigger perspective of a hundred yard field, and the people we see it from more of a top down view, look like ants kinda far away. Just, kinda the close aspect of the game opposed to that far away. You know, it’s a game played on a hundred yards but a single inch can really change the entire game. So, with the Super Bowl right around the corner, who do you think, which quarterback do you think is better prepared for this, based on your perspective?
Eric – So, I don’t know that anyone has ever asked me an easier question in my life. I’m looking at one quarterback who is 24 years old at the end of his third season, and I’m looking at another 41 year old quarterback who has played in the NFL for about 17 years and half of his seasons have ended in a Super Bowl appearance. So, I think I’m gonna go with Tom Brady on that one.
Justin – Yeah, I feel like had I asked you this question with any other pairing of teams, you would have had to think a little harder. But Tom Brady is just one of those names that everyone knows and for good reason. I’m personally not a huge football person. Tom, you don’t seem to watch as much as Eric has this past season.
Tom – Oh, I watch a lot of football.
Justin – Okay, how would you break it down then from your perspective? Who do you think has the better shot?
Tom – Oh, you know, I was actually pulling for the Kansas City Chiefs —
Justin – Weren’t we all?
Tom – And I’m pulling for the Rams and think they’re an interesting story. Great young head coach, so we’ll see what happens.
Justin – Alright, so, one more physics based question and then we’re gonna kinda move to the more safety side of the game. So, what are the physics behind a tackle in the NFL? And, what’s a comparable impact kinda for someone who has never been tackled on a football field? What would that feel like?
Eric – So, the beauty of applying the laws of physics is that we can apply them to the atomic world, we can apply them to galaxies, and we can apply them to football collisions. And the same laws apply. So, we use things like momentum conservation and Newton’s laws to study what happens on a football field. And the types of collisions, you’re talking about players who are well over 200 pounds, sometimes over 300 pounds, and they’ve got 20 pounds or so of padding and a helmet on to add to that weight. And then when they come into collision, you’re talking about a quarter of a ton of mass coming together and the collision force itself average something comparable of that in the time scale of the collision. But, the average force doesn’t tell you how large the maximum force is. For a very, very tiny instant of time the maximum force can get well over a thousand pounds, close to fifteen-hundred pounds. And that is plenty large enough to cause possible concussions if the trajectory is just right. So, the forces here are comparable to, let me give another example from basketball, we’ve all seen Zion Williamson play for Duke this year. And the Wall Street Journal had me do a calculation for what happens when you take a charge from Zion Williamson and it’s like getting hit by a Jeep at 10 miles an hour. And, you gotta extrapolate that to players moving a little faster with padding, with helmets, a little heavier. And instead of some guy sitting there trying to take a charge, you got two players running at each other. So, we’re not only talking about a Jeep going 10 miles an hour but you gotta put a family and a dog and some equipment in the Jeep as well. It’s not for the faint of heart, you’ve got to be in good shape and have good habits and good training on the field to try and avoid injury.
Justin – We’re not used to, in common day-to-day life, talking about tons of mass. We’re used to pounds, ounces, we’re not used to tons coming at you. So, it sounds like it’s a lot more than people are used to. It’s a lot more than you would expect it to be.
Eric – Well, we actually deal with forces like that all the time, we just don’t realize it. When you try to think about how much force it would take to break a table or whatever. If you’re ever swinging a bat and hitting a baseball, the force on the ball and the bat instantaneously gets up to the size of a ton. But, you’re talking about a very solid wood object and a ball that can compress a little bit, but try and imagine compressing that ball or that bat with your fingers. You’re just not going to be able to do it. So, you’re gonna be able to push with a hundred pounds if you’re pretty strong with your thumb, but now you need to add another zero to that if you’re going to talk about it actually hitting with a bat.
Justin – So, you mentioned concussions a little bit, and that this force can definitely cause concussions. So, let’s move a little bit in that direction. Tom, first off, what is a concussion specifically? And how have you been studying them?
Tom – Yeah, so if you look at the consensus statement on concussion in sport, the textbook definition is, so to speak: traumatic brain injury induced by mechanical forces. So, what does that really mean? Concussions can be caused by an impact not only to the head but to the face, the neck, on another spot on the body that can cause the head to accelerate rapidly. And, when someone is concussed, they have a rapid onset of transient symptoms, meaning that they last a short period of time, they spontaneously resolve, and the patient gets better; usually within 7-10 days but there is about ten percent of the population that is concussed, their symptoms last longer than 10 days. So, that is a possibility.
Justin – So, what is actually happening to my body during a concussion? Right, so, Eric charges me, tackles me to the ground, I get a concussion, what’s actually happening inside my body at that moment?
Tom – Yeah, so this injury is at the cellular level, so it’s more than a functional disturbance rather than a structural injury. So, if we do a CT scan or an MRI, for the most part, those are going to come back and look normal. So, structurally the brain looks the way it should. The only way we see this injury is if we do more complicated imaging, such as an MRI where we have the person doing some sort of a cognitive task, then we can see the fact that their brain is working a little bit differently. And so, it’s a functional disturbance, it’s at the cellular level, we think that it is neuronal stretching. So neurons are brain cells and they get stretched and the neuron’s job is to move information from one cell to the next and when they get stretched and their myelination gets destructed and the signal doesn’t transfer quite as well as it would normally. That’s one thought, there’s also a couple thoughts about a capillary disruption in the brain being part of it as well.
Justin – Alright, that sounds very unpleasant actually, like that does not sound like something you would want to have happened to you.
Tom – A lot of people when they have concussions have a host of symptoms. They can range from cognitive base, so from thinking, paying attention in class; to symptoms, they have a headache, they’re sensitive to light or noise, or they feel nauseous, some patients will have balance disturbances, they’ll have trouble standing on one foot, they’ll feel uneasy. And then some other folks will have ocular motor issues, where they have trouble with saccades — or moving their eyes quickly in one direction to the other — or near point of convergence, where both of your eyes kinda look towards the center.
Justin – So, I’ve heard probably more about concussions in the last four or five years than I have in the rest of my life. And it seem like more and more people are knowing what concussions are and concerned about concussions and obviously in a game like football where concussions can definitely happen, what is actually a helmet doing? What is the NFL helmet doing as far as preventing or lessening a concussion?
Tom – So, if you look back at why helmets were introduced into the game, and how they are certified now, the key is, their purpose is to prevent skull fractures, subdural hematoma, and more life threatening injuries. The purpose of a helmet is not to stop a concussion, yet. And if you think back to our conversation on how concussions occur, you can get a concussion by taking a blow to the chest if your head accelerates fast enough. So, there is no helmet that will ever prevent all concussions because you don’t have to be hit in the head to suffer from a concussion. But, if you think about what helmets are for, the subdural hematomas and skull fractures, those are very rare in helmeted sport, we just don’t see those injuries. So, helmets actually do a pretty good job at what they are intended to do. I think right now there is a bigger push for helmets to work better for concussion and there is a lot of work being done in that area now to help move that process along.
Justin – So, what is specifically being done? Because the NFL has come under a lot of fire, specifically the last few years. Are they aware of this? What are they trying to do to push safety and kinda protect their players as much as possible?
Tom – Well, from a helmet standpoint, interestingly, the NFL does contract an outside group of researchers to study their helmets and in all locker rooms there is a poster that rates every helmet on the market that is rank ordered. Number one is the best, number two is the second best, and on down the list. And interestingly, players are allowed to choose whatever equipment they want. The player’s association does not mandate one particular style or brand or that sort of thing. But I think, we’re getting closer to the NFL banning certain helmets based on how they score. I think that the scoring is probably a good thing, it has forced manufacturers to make better helmets. I do have some questions about, are we just making helmets that test better or are we making helmets that are better for preventing injury and you know there may or may not be a disconnect there, in most of the work that is being done now, they are doing reconstructions of the concussions that happened on field to better study the mechanisms and the accelerations that the brain is receiving so that they can make helmets to better withstand the actual causes on the field. Some other things the NFL is doing, they’ve changed rules quite a bit, even over the last 4 or 5 years. The kickoff is substantially different. Off the cuff, I’m not sure what percentage are touchbacks, but it’s a lot higher than it was 4 or 5 years ago. So, they took a look and said the kickoff is one area where a lot of injuries happen, and so they moved the spot where the kicker kicks the ball up and now if you notice players who want kick coverage have to be within one yard of the line of scrimmage, they can’t get a running start into the kick. So, they made that change. And then the targeting rule, we probably see this a little bit more in the college game than we do in the professional game, but certainly it’s in both. In the college game, if a player makes forcible contact to the head or neck area of an opposing player he is disqualified from that game. It’s a tough rule and I understand people who don’t like it from a sense that it’s a very face paced sport and making split second decisions is really, really hard on defensive players, but the reality is, the player’s safety should be the number one priority.
Justin – Absolutely. So, this question goes to both of you, based on your own research and your fields of study, what do you think is going to be different about football in say, 5 years? You talked about how in the last five years its changed, what do you think is going to happen in the next five? Let’s start with Tom this time.
Tom – Yeah, so I didn’t talk about some of the work that we are doing here. So, we are involved in a clinical trial at the moment, studying recovery from concussion, and the study is called Active Rehab. It’s a joint effort, the principal investigators are at the University of North Carolina at Chapel Hill and the Medical College of Wisconsin out in Madison. Essentially what we are doing is looking at concussed patients, the recovery trajectory is to let the patient rest until they feel better and then once they feel better we slowly start introducing activity back into their day. And what we’re doing with this particular study is treating the patient individually before they come symptom free. So, for example if somebody has a headache, maybe we’ll do some massage to help ease their headaches or if they’re having balance disturbances, we’ll do some balance drills to help improve their balance while they’re still recovering before they return back to play. And so, I think that this is promising. We don’t know which one is better, straight up rest or some type of active rehabilitation. We hope to have some answers in the next coming years. This is the first randomized control trial done on this, but there is some anecdotal evidence done on this to suggest that people are going to recover faster. So that’s one thing. The other thing that is interesting and how it might look in five years, I think the helmets will definitely change. VICIS is a company out in Seattle, they make a much different helmet compared to the other ones on the market. The shell is much more flexible, I guess is maybe the right word to use, pliable. Their market is gaining in size, they just released a youth helmet. And I think they’re interested of getting into the market with some other sports as well.
Justin – That’s really, really cool. Let’s go ahead, Eric, going back to the physics a bit, NFL has had you working on the quite a bit. The NFL is at least aware that physics do impact a lot of the game, but how do you think that’s going to impact the NFL in the next few years?
Eric – Well, and Tom was just spot on with his discussion of the concussions, and what you want to think about in a really gross, simplified way is the brain sitting in this fluid and we walk around and we start and stop and that fluid is going to really provide a little cushion. The G forces that have been measured in some studies show that some of these football collisions, these helmet collisions, can get up to over a 100 G’s. And you compare that to a car crash, where studies show about 30 G’s and the flash fighter pilot’s at about 10 G’s, though they experience that a lot longer, these are really large accelerations. And I looked at the collision at the NFC game, where Josh Hill sustained a concussion from a hit from Cory Littleton, and this was in the first quarter, in the latter part of the quarter, where he took a blow from the side, but it was right on the helmet and, not trying to provide a whole lot of causation but just to give you some of the numbers here, you’re talking about 500 pounds of players coming at each other, you’re talking about G forces that very instantaneously can reach 100 G’s. And what the helmets got inside of it, it helps with what’s called linear acceleration with the padding, if you jump off of a chair you’re not going to land on the floor with your knees straight, you know with your knees unbent, with your legs straight. You’re gonna bend your knees. You know your airbags in your car is doing something similar to the bumpers on your car. What it’s doing, it extends the collision time, and when you extend the collision time, the force goes down, and when the force goes down the acceleration goes down. So the padding with a direct impact can help extend the collision time and reduce the acceleration. What the helmet is not really good at, and what the NFL is trying to get some more studies to help with, is the rotational acceleration. You can have all the padding you want on a helmet and, like Tom had said about getting hit in the chest, I mean if my head just rocked really hard to the side, even if I’ve got a helmet on with a lot of padding, that rotational acceleration would still be large. My brain could still impact against my skull with quite a lot of acceleration. So, it’s really hard to tackle the problem with the rotational acceleration. And as far as the future, I think that the NFL is going to try and work on that problem. If you start looking down at lower ranks, a lot of schools, high schools and stuff are giving up football. It’s not just the safety reasons, it’s the cost. Because the insurance cost on the players that they have are skyrocketing because of these concussions. So, a lot of them are actually finding it too expensive, not even just the equipment point of view but from the insurance premiums are getting really high that a high schools are dropping football for that reason.
Justin – That’s really interesting. So it definitely seems like football is going to be in a different place in 5 years. Well thank you guys both for joining me today. It’s been a pleasure having you. And I think we will see you all next time. Bye.
Tom – Thank you.
Eric – Bye-bye.