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Transcript: Media Availability with Dr. Allen Sills and Jeff Miller – March 1, 2019

The NFL analyzed its most recent injury data during the medical committee meetings, which took place in Indianapolis ahead of the 2019 Scouting Combine. The injury data is compiled and analyzed by IQVIA (formerly Quintiles), an independent third-party company retained by the NFL. For more information, see the injury data page.

The following is a transcript of media availability held during Combine.

SPEAKERS

  • Jeff Miller, NFL Executive Vice President, Health and Safety Initiatives
  • Dr. Allen Sills, NFL Chief Medical Officer

NFL CHIEF MEDICAL OFFICER DR. ALLEN SILLS AND NFL EXECUTIVE VICE PRESIDENT OF HEALTH AND SAFETY INITIATIVES JEFF MILLER: MEDIA AVAILABILITY

MARCH 1, 2019, INDIANAPOLIS, IN

Jeff Miller: So, the purpose of this is to chat with everybody about our Combine week, because as you know, this is the culmination of a lot of planning and effort and statistical analysis and the convening of a lot of our medical experts. All of our medical committees meet here; our engineering committee meets here. Increasingly, and I can get to this in a moment, we meet, Allen and I do, with coaches, general managers, and frequently with the Competition Committee to share some of the analyses that we've done about play types and injuries. And those have been increasingly productive and fruitful conversations. We have gotten feedback from a lot of our medical experts. Allen can go through all of the committees if he chooses. They are numerous, and we are blessed to have a lot of really good people working with us. This makes for the really long week for us, which for me is over. For Allen it is not – he's got a little more to do, as well as meetings with the NFL Physician's Society, the Professional Football Athletic Trainer's Society, and other medical organizations that all contribute to the health and welfare of our players. So, it is a great week. It is a long week, but it's been good.

Why don't we just quickly go through the highlights of some of the things we discussed for your purposes because we told you coming out of Super Bowl that we would have more to say as we did more analyses. We have done a lot more, not that that is ever going to stop, but we will share with you some.

So, first topic of conversation that came up in most of our meetings was around our concussion reduction strategy: the effort last year that we put together to try to drive down the number of concussions. The three pillars of that were: 1) concussions in preseason practices (and we have some insight into that), 2) helmet choices of players, and then 3) some of the rules changes — lowering the head rule — use of helmet rule, excuse me, lowering the head behavior, that we talked about with the Competition Committee a lot last year and then their request that we help analyze the kickoff play for some changes. So, stopping there and giving you the answers to that.

As you know, concussions in the league last year were down 29% in regular season games. We think that that's an important number. But, that there is still a lot of work to do. For example, in the preseason practices, we did not see a decrease. The numbers were exactly flat. We define preseason as the first part of training camp, before the preseason games start. And as we were digging into that, we made a few observations which we shared with the coaches and the Competition Committee. Disproportionally, the number of concussions suffered in preseason practices are to offensive linemen. More than one quarter of all concussions, that number is 27% this year, but that is not an odd number on a year-over-year basis, were to offensive linemen. And about two-thirds of concussions are in blocking behavior which is the opposite of what you see in regular season games. Not a huge surprise because in preseason practices there isn't a lot of tackling to the ground. So, there is a lot of emphasis on blocking. And lowering the head behavior was one of those components. Interestingly, as we did an analysis of the offensive line, we saw that very few — and this is true in regular season games as well — very few, if any, of their concussions occurred at the line of scrimmage. It was not coming out of a three-point stance and hitting each other. Rather, it was mobile blocks. Somewhere in the orders of the magnitude of ten times or twelve times, it was mobile blocks, as opposed to run or pass plays, for the concussion rate for offensive linemen. So, when they are pulling, when they're out in space, when there are screen passes, that kind of thing. Which, I don't think suggests a rule change in any way, but it does suggest a coaching or education point for offensive linemen. I think one stat that came out was the median yardage for a guard when he suffered a concussion was seven yards from the line of scrimmage. So, he was moving.

Question – That is practice or games?

Miller: That's in games.

Question – Games in the preseason?

Miller: Games in the preseason and regular season in that case.

That is all games. I jumped from the disproportionate number of offensive line concussions in preseason practices to looking at the offensive line in general. So that is an education point and that is something that the Competition Committee asked us to take a look at and that they'll spend some time talking about over the next few weeks as we look to drive down those numbers.

The story on helmets, this was the second pillar, as many of you know, is a very positive one. It was a result of a really good collaboration with the Player's Association, with the players themselves, with the equipment managers and our training staffs, we moved one-third of the league last year to the green or the best performing helmets.

Dr. Allen Sills: The total number is 74%, you are saying one-third increased into green.

Miller: Right, so now we are at 74% of NFL players in the green helmets. That leaves 26% that aren't and that will be a goal for this coming year, to move more of those players into the better performing helmets. Interestingly, in the helmets story, and we are still part of the way through this, is there were ten new helmet models introduced that have been tested by the league, I think this was the most we have seen.

Question – For last year or this year?

Sills: Coming into 2019.

Miller: So, from the perspective of innovation and a level of dynamism in helmets, for improved protection, we are seeing a lot, which has been a point of emphasis for the league for a while. As you know, we have put significant resources into engineering work and as we've learned more and shared more with the helmet manufactures, we are starting to see the fruits of that in terms of more protective equipment for players. And I think that we are getting close to the day, in the next couple years, where we will start to see position specific helmets as we understand what each position feels. We talked about offensive line a moment ago: they see a lot of lower impact but more frequent head contacts, helmet contacts. A corner or a safety sees very few but they are at high velocities, and yet, they still wear very similar equipment. The day is going to come soon when the manufacturers will build things different for them based on their own individual circumstances. And our own engineering work will support that. So, we think that the analysis shows that players wearing green helmets had a lower concussion rate than those in the red helmets and it was a substantial difference.

Question – Do you have numbers on that?

Miller: I do have numbers.

Sills: 38% reduction. 38% if you go from red to green. If you go from yellow to green its 15% reduction.

Miller: And that is based on this year's data. So, you know, we share that information with the players and such, and we are not saying that a helmet is going to protect you from a concussion but, there are differences based on the equipment that you chose.

Sills: Two things that I think is important to point out there is once again the engineers did a correlation this year between how the helmets tested in the lab and how they did on-field, and the correlation is still very strong. Meaning that the lab tests actually predict the injury rates on-field. So we have a high degree of confidence when saying that the green helmet performs much better than a yellow or red helmet, not just based on the lab tests but actually based on what happens on-field. So, that is an important educational point because obviously when you are asking players to make a change, it is one thing to show them a lab test but, but when you can show on-field rates, obviously, that is a very persuasive argument. So, that is really important work that continues to strengthen the helmet testing. And I think just speaks to the fact that our engineers from the league and the Player's Association are doing some of the most sophisticated and advanced helmet testing.

Miller: It's a great collaboration. It's a great point. The partnership there is as strong as it could be and I think it shows in the results that a lot of players made a choice to move. The data is there. The Player's Association is working on it. There is more to do, but it was a good first step.

Sills: The other thing that I think is interesting about the helmet story, not to get drowning in numbers but, 50% of players in the league changed their helmet last year and they moved up an average of about seven spots on the helmet poster, you know if you look at the ranking. That is an enormous change in one year for a piece of equipment that I think again speaks to the educational efforts on behalf of the Player's Association and the leadership of the players themselves. But also, the acceptance of how important this issue is and how reliable the testing has become. So, we are extraordinarily pleased to see that. And we also know, as Jeff likes to say, the works not done there either, because helmets will continue to get better and some of what is green now will be in yellow in a couple of years just like its very analogous to our cars, right. The safety technology continues to get better year over year and the 2019 models are safer than 2012 or safer than 1998. We think helmets will track the same way. So, the movement of players into helmets will probably be an ongoing story as the technology continues to improve.

Miller: It is a culture shift.

Question – When will you re-rank the helmets? Because some will move from yellow to red right?

Miller: We are working on that right now. I imagine that we will probably have something in a few weeks' times.

Question – Will that be done for this season?

Miller: Oh, for sure, it will be done before the players come to training camp.

Question – So, if a helmet moves from say yellow to red will players have to get out of red?

Miller: We are going to have that conversation. We'll have that conversation with the Player's Association. I think last year we set a standard that if we prohibited helmets we gave a grandfather year. So, I think that is probably a standard that we will set going forward. We will give players a year to change.

Question – But the guys that were in last year, who were in red…

Miller: There are 32 remaining that are in red as of Week 17. Which is easy to remember because we have 32 teams. And so yes, we'll work with them to give them choices. And the point about ten new helmet models that the manufacturers are introducing means there are lots of choices. That is a good thing. And hopefully those will test well. I am not making any news on that because I don't know. But hopefully they will test well which will give players more alternatives.

Then the last pillar of the concussion reduction plan was around game play, around the rules. And I know there was a lot of conversation around the use of helmet rule. And here is what we saw. We saw that use of helmet behavior, that led to a concussion, I mean lowering the head behavior that led to a concussion, decreased by about 20% this year. Now, it still is involved in about nearly half of all concussions from helmet-to-helmet contact, but it is down significantly from last year. So, that is one data point. It is one year. That is not a lot of information. Helmet-to-helmet contacts causing concussions that number is 20% lower than it was a year ago. So, that is positive thing. There's obviously a lot more to do in that space. That is something that was very interesting to the Competition Committee as they continue to push and make an emphasis on this point. So, that is a teaching point, a player adoption point, a culture change point and a good one. 20% down is nothing not to emphasize but, there is still a lot of helmet-to-helmet contact causing concussions

Question – What is the real number? Not the percentage but, the real number.

Miller: I can give you the raw number. How many were different, yeah. Still in terms of cause of concussion, and this is a point that we use as a metric, 40% of all concussions are still caused by helmet-to-helmet contact. Period. Forget the lowering the head behavior. Just two helmets colliding results in 40% of the concussions. So that still is a significant number and one that we want to continue to drive down. This rule change is a big step in doing that and we began to see some behavior change. Do you want to comment on that?

Sills: No, that's all the key points and one other thing that we looked at is that tackling is a big component obviously of the lowering the head behavior and the use of helmet. Jeff mentioned in preseason, that blocking is sort of the dominant activity, obviously concussion in games are more associated with tackling, I think it is 64% of all concussions are related to the tackle. And that actually is both involving the tackler and the person being tackled. And so, we continue to look at that interaction and how we can improve the safety of it and obviously that goes back not only to the rule but to education. And we spend a lot of time sharing that data not only with the Competition Committee but also with the players and the Player's Association and really focusing on that aspect of it.

Miller: And the coaches and the general managers. And others who are very interested.

Question – Any breakdown on the offensive versus defensive because that was obviously a big question coming into this season with the rule-wise, how are you going to call the offensive player for lowering the head. We saw that a little more in the preseason and then not really at all and then a little bit as the season went on.

Miller: In terms of calling it, I will leave that to officiating. That is not really our domain. But, as a result of injuries, we saw a much more significant decrease in concussions on the offensive side of the ball than on the defensive side of the ball this year. Because remember we saw an overall 29% decrease in concussions in regular season games, but they were disproportionately on the offensive side of the ball. Not the defensive side of the ball.

Question – That was the overall decrease in concussions?

Miller: Overall. And it was disproportionately on the offensive side. So we wrestled with that issue a lot this week. I am not sure we reached a conclusion as to what that means necessarily but it's interesting.

Question – When you say on the offensive side of the ball it could be an offensive player being the one lowering their head, or it could be the recipient?

Miller: That's exactly right. I think there will be a lot of video review to take a look at that and try to dissect if behavior is changing. Anyway, it is good news for the offense, but it requires further investigation.

Sills: Jeff brought up one really good point about that – everyone wants to say okay, you made a rule change now what is the effect? You know, one season, while it has a lot of data, is still in the scientific sense a small data sample. And so, there is a lot more analysis we have to do with that to fully understand. Plus, there are a number of variables that changed. Not just the change in the rule, right, there were helmets that were changing and the emphasis on the helmet-to-helmet contact, the kickoff. So, in the scientific world, if we change one thing then you can say, okay the change we saw is related to the variable we changed. When you change four or five variables it becomes harder and harder to tease out which was the one that seemed to have the most effect. But clearly, they all played some role.

Question – That to me, as someone who is just viewing the games, seems is the biggest culture shift. For the offensive player to bear some responsibility in that.

Sills: Yes, but again remember the tackling is you know, it's a two-part equation on the tackle that's there. And so, there is shared responsibility in that.

Question – Had you guys looked before, down 20% for this year, or for '18, did you have numbers from '16 and '15?

Miller: I don't have them top of mind.

Question – How were concussions on kickoff returns?

Miller: On kickoffs, that was the other part of the concussion reduction strategy, so thank you for the seg-way. Concussions on kickoffs were down 38% over the last three-year average. So, we looked at '15,'16 and '17 where there was no rule change versus '18 where there was, and we saw a 38% decrease. Allen made the point before, wisely, that part of that could've been better helmets, part of that could've been less lowering the head behavior, so there is a number of different variables there. But that 38% was interesting. When we did the video review of it, we found the primary decrease in concussions was caused by the elimination of the blind side, or the double-team block. Not having that blocking behavior in there seemed to have a significant concussion savings for the players involved. There was discussion around the speed of the play – potentially taking some of the higher speed out. The players still reached peak velocity on the play. It was a tick later because they were coming from a standing start but, the configuration of the play and the elimination of blind side blocks or double-team blocks seemed to have a significant contribution to that decrease in concussions. So, 38% over a three-year average is pretty good. Allen points out, he's right, one year. You know it seemed to have the result the Competition Committee wanted but one-year of data on kickoffs, especially a play that doesn't happen that often, compared to plays from scrimmage, is not a lot to hang your head on. But, it is good news anyway.

Sills: The overall injury rate went down on kickoffs. It wasn't just concussions. All injuries were down on kickoffs this year compared to that three-year average.

Question – Is there something there that you except to be extrapolated when they look at the punt?

Miller: The punt is a point of major conversation so, again, you guys are leading us right to the things we want to talk about which is great. So, the Competition Committee asked us to take a look at the punt similarly to the way we looked at the kickoff last year and the injury rate on the punt is substantial when you talk about major injuries defined by injuries that cause players to miss more than eight days, that is our definition of substantial injuries. 10% of all injuries in the NFL that fall into that category, major injuries, are on the punt play. Which is vastly disproportionate to the number of punts you have. And you're talking major injuries like ACLs, broken legs, that sort of stuff. And so, we are looking at it from that perspective but also of course from the concussion perspective and as you know we even ran a data analytics competition around Super Bowl by giving out 600-some odd punt plays to a bunch of data scientists and asked them to come back with solutions for us. And one thing that those folks recommend, and our engineers corroborated, and we shared with the Competition Committee was the expansion of the definition of blind side blocks, so not just blocks to the head and neck but, blocks coming back to the goal line or parallel to the goal line, I'll leave it to them to define. The elimination of those would have substantial injury savings on the punt play. One-third of all concussions on punts occurred as a result of my expanded definition of blind side blocks, or our definition of blind side blocks. If you eliminate those you are saving multiple concussions a year. Likewise, a substantial number of those major injuries that I described are as a broader result of the broader definition of blind-side blocking. I don't remember how many it was exactly, but you're talking a couple of dozen, at least. Significant time lost injures are a result of the potential broader definition of blind-side blocks. The competition committee, you know, will do with it what they will and they'll discuss that at length. We share that with special teams coaches in meetings, general managers, too. I am just trying to recall all the meetings, there have been so many. And so many presentations and it was a very active and interesting debate about how you would define it, how meaningful it was, and I'll leave it to them. That's their domain and not ours. But, if you eliminate the blind-side block on the punts… to the head and neck, I'm talking about any, all blind-side blocks, if you don't see somebody coming, we can show you some video, and you receive a blind side block and you're driven into mark, we've seen examples of players blowing out their knee because their teammate was blown into them or guys hitting their head because they're in a bad place as a result of the blind-side block.

Sills: And it's not just the blind-side block on punt plays, right? The blind side block on turnovers, for example, is a major problem, too. When there is an interception, fumble, all of the sudden you got defensive players on offense and vice-versa. The blind-side block is a risky situation. It's a risky play on any play situation – punt, turnover, etc.

Miller: I think that will be a continuing conversation.

Question – Back to kickoffs for one second, you said concussions on kickoffs were down 38% over the 3-year average. Do you know what they were down year to year? From the year before the new rule?

Miller: Last year was 20%. Preseason and regular season games this year was 13%. My math. After doing 32 over 32, I can no longer do math.

Question – And that's preseason and regular season?

Miller: Yeah. Preseason, regular season total.

Question – And you also said the players were still reaching peak velocity, so that suggests the collisions were just as violent…

Miller: No, because the formation was different. Because remember you now have eight guys up in the box.

Question – Do you change the direction and the angle?

Miller: You change where the collision is happening. Many of them are happening before the players reach peak velocity. The runner may reach peak velocity. The player can still reach his velocity, just not necessarily before those blocks.

Sills: This is probably also, although [INAUDIBLE], you change the type of personnel that are on the field. Right? Because when the guys have to be in that, what do they call it? The zone up front. The formation zone.

Miller: We'll go with that.

Sills: You've not got to turn and run back down the field on the kickoff.

Question – The no-blocking zone…

Sills: Correct. So, I mean we heard from coaches and others that there are changes in the type of personnel, so that is also going to change where and how the collisions occur.

Miller: I think the number was more than, forget it, I'll get it wrong. I'll come back to you with it, the number of defensive linemen. But, Allen is right – they were replaced with linebackers and running backs and others.

Question – You talked about expanding the definition of blind-side blocks, that would be for all plays or just punts?

Miller: Up to the Competition Committee. We showed them the related injuries on all plays. From the expanded definition of blind-side blocks and there are, as Allen pointed out, turnovers – big challenge. A lot of risky behaviors going on there. Punts and kickoffs, players moving at high speeds occasionally coming back towards their goal line as you would in a blind-side block, more frequently than you would on a runner pass play. But, that is for the Competition Committee to decide. But, we are looking at, I don't know what the numbers are exactly, that could be attributed to the blind-side blocks. But, you're talking numerous ones every year if you look across all plays and like I said, on-third of concussions on punt plays annually.

Question – So, that is something that the Competition Committee would discuss leading up to the March meetings?

Miller: They will. They will.

Question – Then you mentioned the pulling guards and like the mobile blocks, might be more of a Competition Committee question, but like the lowering of the helmet – I remember a lot of coaches saying that the first year of lowering the helmet the emphasis would be like on calling open field tackles more often.

Miller: It is easier to see.

Question – Right, easier to see. Would the next year be like more attention being paid to some of the mobile blocks?

Sills: I mean, we talk about the lowering of the head behavior anywhere on the field. People automatically assume it is related to the tackle. But it is really, as you pointed out, it can be part of blocking and one thing that Jeff mentioned, it was tucked in there, a lot of statistics was, you lower your head – that's dangerous on any type of play. Tackling, blocking, anything. Part of that makes sense, right? When you're no longer looking at what you're going to hit, you don't make those adjustments, and your placement is not as accurate. We also spent some time with the engineers talking about that lowering the head is not just getting your back parallel to the ground, that flat-back posture. You can lower your head and still not be fully parallel to the ground, that is also a much higher injury risk. So, back to your original question – you can do that in a tackle, you can do that as part of a block, so it is a culture change. It is a teaching change I think around all of the different aspects of the game. We're trying to not just make it about that open field tackle, but to look at it. So, it will be an active conversation. Again, education and enforcement are all part of changing that.

Miller: The Competition Committee, in that case, came to us and asked for the analysis on offensive line, defensive line. So, I think it probably fits with your understanding of where Rich or Troy's heads were. Which was, "okay, we need to take a look at this. When are we going to have time to take a look at it?" So, that is part of our analysis. What they do with that information is ultimately up to them.

Sills: It is harder to make a rule change. And I think another important point is – we think, just in the way that Jeff said, helmets are not going to solve all of the concussion issues. Rules changes won't solve all of these injury issues either. Rules changes and enforcement is part of it, but it is also education and culture and how we teach the game, how we practice, and how we teach the techniques associated with blocking and tackling. That is ultimately going to make the difference. And that is what is so exciting about a lot of this work is – this isn't just applicable to the NFL and NFL players, right? This is safety for football overall and how we teach the game from youth all the way through the professional level.

Question – A new helmet rule last year, helmets down, whatever you want to call it – part of that, that we all learned during the preseason was there has to be intent. Right? Not just random collision. With your numbers with the 40% of the concussions, helmet-to-helmet, did anybody further subcategorize what they deem to be an intended play or not?

Miller: Getting back to how it is officiated is really outside of our purview.

Question – I guess the guys in Virginia with their video, did they categorize helmet-to-helmet hits with intent in mind or not intent …

Miller: No. We look at mechanism of injury – what happened. And therefore, what caused the particular injury, and the frequency of that behavior. The rest of it around how the players can be educated, how the rule can be enforced is somebody else's to determine. So, we bring that to them and then they'll wrestle with it. Do you want to touch a little on the other end of the body before we let these folks go?

Sills: Two points on that – one is that if you saw some of the presentations in the committees, you heard us start talking about this concept of "injury burden." Formanyyears, we've counted the number of injuries and we've told you there was "this many ACL injuries or this many ankle fractures," and we're starting to talk not just about that but, about injury burden – which really means not only how many injuries but, how long were players out? And so, when you look at injuries across the NFL with that concept, there are three injuries that really jump to the top of the chart. Those are obviously the ACL and the knee ligament complex injuries, there are not a lot of them but they miss a lot of time so that burden of – it's basically multiplication, the number of times x time lost – isreally high. But, second on the list are hamstring and adductor strains, lower extremity strains. Maybe a little surprising but, when you think about it, even though they are not out for as long, there are a lot of them. So, that burden is nearly as high as the knee ligament complex. Then the third are the ankle sprains and ankle fractures. So, because those are the highest burden injuries, we really targeted those and said, "We want to attack those." Much inthe same way we did concussions. When we looked at concussions a year ago we talked about a call to action and said we need to put a plan against it. We said, based on the work from the engineers, epidemiologists, our scientists, our medical advisors, we think if we've identified these risk factors, and if we do these things, we could drive that number down. My challenge to our medical committees and our experts now is to do the same thing for these other high burden injuries. In other words, we want to attack the knee ligament complex, the hamstring adductor strains, and the ankle complex in the same exact way and say, "what can we immediately change that will drive those numbers down?" So, an injury reduction strategy is where we're going with that. We hope to have a lot more dataaround that by the end of the year. That is a very comprehensive look at equipment, at surface interactions with cleats, about how we train, when we train, how the calendar of the year is laid out. So, sort of everything is on the table to analyze there and see what we can do to drive those rates down,because it is very clear that the burden of those injuries is extraordinarily high to our players.

Question – Does the NFL keep such injury data as – what type of field surface, what type of cleat whether circular cleats,or what have you?

Sills: So, we are moving that way. Obviously, we've had surface data but one leadership point out of theengineering work is tracking cleats. So, we would like to be able to track cleats and cleat patterns in the same way we do helmets. We can tell you how many helmet concussions per model, and we'd like to be able to do that for cleats, as well. To do that is a really big undertaking, right? You've got to know exactly what shoe a person is wearing all the time.

Miller: Not just on injuries, but you need to know what the denominator is, what the exposure level is, that is a lot.

Question – Turf versus grass. Do you have those numbers already?

Sills: So, we have a working group that's, again, engineers from the Players Association and the League that are working together,and they are also trying to characterize a little further, not to pick on you, but, when you say turf versus grass, when you say artificial turf – we have how many different surfaces? 12. 12 different surfaces. It is a little unfair to lump them all together and say, "turf." Because "Turf A" may perform very differently than "Turf B and C" so we are trying to …

Question – 12 different in use?

Miller: In use, right.

Question – 12 different kinds of artificial turf?

Miller: Well, each one if a different recipe. There are less than 12 manufacturers. But, you know…go ahead.

Sills: I was going to say, each one has not only the artificial blade of grass, but they have sand and rubber mixtures, and how they're mixedand whether there's a pad underneath it, so they actually are different. This gets back to our conversation, John, that you can't say they are all equivalent. So, you see it becomes much more complex right away. You can't just say turf versus grass,butwhat type of turf? So, what we are really trying to change the conversation to is what are the performance characteristics of the surface? Right? Because surfaces have friction, what is the grip coefficient? They have the thickness, the softness, there are a lot of different characteristics and so if you want to really understand the injury risk, you want to say, "what are the characteristics of the surfaces with the higher versus lower injuries?" That is a really complicated analysis. That is what our working group is doing. But, it is not just as simple as artificial versus natural. Also, just to add one more wrinkle of complexity, the turf in Green Bay, the grass in August,is very different than January, right? So, once again, everyone kind of wants to go to the grass versus artificial – it is just not that simple. So, there is a lot of work to be done there, we are doing that work but, it is, as I said, a lot of engineering to understand the characteristics of the surface and how those may change. How we can measure that and then correlate it to injuries, obviously that is the goal.

Sorry, that is a very long answer to your question. But, it is important for people to understand because we often get asked, natural versus – it's a lot harder question.

Miller: The only other thing I would add to Allen's point – it is a multi-year effort. We're not going to see significant changes tomorrow – this is going to take a lot of time.

You might not even know all the variables for a few years…

Miller: No. This is going to take a lot of time.

Do teams even report what kind of cleats players are wearing? How about when players go in and change/switch? After they warm up, they change their cleats.

Sills: Welcome to our world.

Miller: And the cleat will perform differently on grass versus Turf A versus Turf D. All of that are things we need to involve.

Sills: You start to understand why it's a harder problem to solve. But, we are committed to attacking it and doing it in a thoughtful way and doing it with data. Not just with anecdote.

Miller: It is going to take a lot of time.

Sills: I thought one of the most significant things, and we both commented on this, both Jeff and I spent just as much time this with Competition Committee and coaches and general managers and owners as we did with medical people. And I mean that in a healthy sense, meaning that the level of engagement that we have with all those individuals is terrific,and they are asking for more and more data. Just like Jeff spoke about – analysis of the punt play or the kick off, they want us to bring them the data. I had the opportunity to sit down with the Coaches Committee this week, all the head coaches, and we showed them our data,and they were incredibly engaged with that. They wanted more, they wanted to show the data to their players, they wanted to show it to their coaching staffs. So, I think it is a testament to the culture change of how the rule changes and the techniques and the teaching of football is now being driven out of this data and out of the medical considerations. That is true at every level – coaching, general managers, ownership, league administration, Competition Committee. It is a really exciting time to be part of that because I think as we look to how we can improve health and safety, it is not just Jeff Miller and I working on this – it is everybody in the league that has really rallied around that goal. So, that is fun for us and exciting.

Miller: That is an important point to add.

Question – Training camp versus preseason concussions, I just want to be clear in defining training camp –

Miller: For us, it was before the first preseason game.

Question – Is what?

Miller: Is training camp.

Question – Before the first game?

Miller: Yes.

Question – Maybe I wrote these numbers down wrong, I had like 20, 31, 31, the last three years in training camp..

Sills: 45 overallin preseason. So, if you take all of preseason which includes the training camp practices, it was 45 in 2017 and 2018. Training camp was 31 in 2017 and 31 in 2018.

Question – That is before the first preseason game?

Sills: Correct.

Question – But, there's no tackling?

Sills: In training camp, there's some tackling in training camp, not too much.

Question – Before the pre-season game?

Sills: Yes.

Question – But I wrote down that like, for instance, I'm just trying to understand it – I had 31 training camp concussions this past season,and only 14 preseason. The majority of what wecall training camp is after the first game begins. It just seems like it would be a disproportionate number before tackling begins. Do I have that wrong?

Miller: Not in terms of the intensity of the practice.

Sills:The overall preseason concussions did go down. Right? [INAUDIBLE]

Miller: Because games went down. But, preseason practices did not

Sills: The preseason total number was 91 in 2017, went down to 79 in 2018.

Miller: So, a 13% decrease. But, preseason practices were level.