Exercise Science and Research: Insights, Agility, and Mechanics with Will Reed

You can find me at refsneedlove2oocom , on Instagram , tiktok and now YouTube . Today we have a very special guest , a bit of a departure from where we've been in the past . We are joined by Will Reed . He is a referee and a researcher with a master's in exercise science who has done a very interesting study on assistant referee performance .

I can't wait to learn more , will . Welcome to the show . Thank you . No , it's a pleasure . Outstanding Will . We actually had a wonderful opportunity . We have met briefly , but we actually got to meet outside of the , I think , the Copa America match . My son and I were there and we got to meet out there . Yeah , no , and what a match it was .

Yes , I wish it ended differently . Wish it ended differently . This is fair . This is fair , yes , but I'll say it was so good to get an opportunity to meet you now via the podcast world as well . Connect a second time and learn a little bit about the research that you've done , but would you mind telling our listeners a little bit about your referee story ?

I had been working with the exercise science majors club for a while and he knew that I had a passion for soccer , so he threw it out there as hey , if we're looking for referees , we have an education clinic coming up in a couple of weeks . Come on in . Of course , for me , I hadn't played soccer in years , but I loved the game .

I was like cool , let's come on in , let's see where it goes , and then the rest is history . I've been a grassroots referee now for about three years . The hope is come . This spring I'll start looking at some of those advancement options with the hope of pushing on to regional here in the next 12 , 18 months .

For the U18 , U19 academy matches , I did a little bit of UPSL last year . That game speed is really intense , not going to lie . But my hope is I'll do a little bit more of that in the coming season so that I can really push that certification .

So I'm going to , I'm going to , I'm going to save my question for that in a little bit , but it's definitely a good segue there . We'll come back for a second . So you've been reffing for three years now , and so what is it that you like or love potentially about being a referee ?

As far as being a ref , though , being able to stay close to the field and being able to , on some level especially with the younger players educate to some extent . Right , it's yes , I'll make the call , but when they're asking the questions , being able to explain to a younger player , this is why we're making that call .

This is what's right , this is what's wrong . I love being almost like a teaching figure . Of course , on that higher level , it's just cool to be on the field . It's great exercise . We get paid for it .

Right , we can talk about what we will about level of pay , but the fact is you're out there you're out there , you're getting paid to exercise and being able to do that with sport , I love it's .

But there is a scientific study that people who attend sporting events are happier people in general , that there's something about coming to a sporting event participating in your community , like you're at a community event , seeing other people experiencing joy , experiencing pain , but experience emotions with other people is a positive thing in general .

So I do think there's some valid data there that supports what you're saying about just being connected to the game . Man is a positive thing for you emotionally and certainly as a referee , physically as well , as there's another study in there .

But what about referee research ? How much is there out there on specifically referees , their performance ? Can you give us some idea of what the current landscape is ?

Thus far , as you said , there's millions , if not potentially billions , of dollars invested into players , player research , player performance , whereas on the referee side , probably not more than a couple hundred studies have been completed .

Now , of course , a couple hundred sounds like a lot , but when you compare that to the amount of research on players , it's frankly a little depressing . Most of the research on referees also focuses on two things . One it's either the accuracy of their calls right , are they getting the right call ? What percentage of the calls are correct ?

How much of it is something that's up for interpretation of the laws , right . And then , of course , there are a handful that are on performance , but they're , at least from our perspective as exercise scientists , relatively baseline . We're not looking at super advanced metrics , we're looking at distance covered . We're looking at , maybe , top speed .

It's more about overall gain metrics as opposed to within gain performance . Right , how quickly are you getting to the end line ? How quickly do you have to move to maintain your position for the ar with that offside line ?

So I have seen a few studies and again I'm just going to say out loud some of the things that I have seen out there . And I'm curious for your thoughts about the validity or accuracy , because I'm sure you had to look up these studies .

I know there is a number of studies , not necessarily all recent , and I know there's questions about the validity , but just referee accuracy in their decision-making , can you talk a little bit about just basic levels , high level of what you know about how accurate in general referees are in their decision-making ?

So I'm sure you had to read through some of those .

Generally , those referees are getting 90 , 92 , 93 plus percent of their calls correct . All of the little mistakes , all of the little parts of play that a referee has to get right on any given day , they're getting the vast majority of these .

Now , of course , no matter what the call is , if you're in a stadium , at least half the fans are going to be pissed with . Whatever your call is right . But the fact is , on a play-by-play basis , referees at upper levels , professional levels , tend to be really accurate .

Now , of course , when we bring in something like VAR getting this opportunity to take a second look at things , it says it in the laws , right , there is the caveat , there is the clause , and it has to be a clear and obvious error .

It's my own personal pet peeve , right , it takes the humanity out of refereeing to some extent , but at the same time , there are instances where it's important . Right , there will be clear and obvious errors that a referee will make right .

A goal might cross the line by a matter of an inch and they have to call it back , but they might not see it on the field , and that's what VAR is there for . But that's going to fall within that really small margin of error , that 5 , 7 , 8% of calls .

Oh , he dribbled away , it's not a foul . It's like you're there's constant decisions that you're making as a referee and those are could be correct decisions incorrect .

But there's lots of decisions out there and obviously we have throw-ins and corner kicks and goal kicks and there's maybe , you know , in a game , 10 or 15 key match decisions where there was a foul close to the penalty area for attacking , for a kick in the penalty area where it could be a penalty kick .

And again , those are high pressure , high intensity types of situations and , yeah , there could be a mistake .

On the whole , again , at the professional level referees , you know around that 90 accuracy , which is just amazing considering it's a human being standing on the field with other amazingly talented and fast human beings who , by the way , who also may potentially exaggerate contact when it happens . They could . It's happened , I don't know . Has it ever happened ?

There's research out there on specifically ref decision making and then the other thing that I've seen , some data is around the distance covered by referees as well can Can you speak a little bit about that , about distance or top speed , I think you mentioned Absolutely yeah , and top speed is still a little bit of a shaky factor because , again , depending on the

game , top speed is still going to be a wide variety .

Most of the research suggests that , at least for the center referee , the distance traveled in any given game is strongly correlated with the distance the players cover . Right , and of course everybody's looking at the field . They're like , okay , but the referee is not sprinting like the other players , they're just in the middle of the pitch .

They have to be wherever the play is Right . If we're talking about a defensive action strikers forwards up top , they might be walking around , they might be standing still . Referees still have to move .

On the other hand , say , you're on a corner kick opportunity referees constantly have to having to adjust in that attacking area so they can get a good view of the play . So , no matter where play is on the field , while certain players may get a rest .

A center referee is constantly having to travel back and forth , even if , necessarily , he isn't challenging for a ball . Overall , those distances tend to look anywhere from six to 12 miles . Looking at performance on the field , in a game where there's a lot of counterattacking actions , that distance is going to skyrocket .

If one team is highly possessive , referees just move in laddery a little bit . It might be closer to six , but the fact is , whatever players are covering , center referee is probably pretty close 12 miles .

And again , I don't know if this is fact or just you know random anecdotal evidence that I've heard , but is it true that research shows that the center referee actually , on average , covers more distance than the average soccer player ? Position player Absolutely so .

correlated . If players are traveling more like in a game , a lot of back and forth referee travels more . On the other hand , if it's a game where there's a lot of possession in one half , they're not traveling as much . Again , the referee is involved in every aspect of play , whereas players they have their defined roles right .

Unless their coach is like you're a free-roaming , go-everywhere type , you're not going to be traveling as much as the center referee . So I can't definitively say yes or no . I would lean toward yes .

But aside from those folks , I think those center referees really do cover more distance . Again , it all depends on the game . If you are Luton Town playing Manchester City and you're having to sit deep in a low block and city's got 80% possession , the center referee is not covering that much distance , but neither are the players .

You go online whether it's to publication journals , whether it's to Google Scholar , whatever you do and you search for research and you read and read and read and read . I've probably got 120 saved articles just that . I went through for my master's thesis and , frankly , what I found was what we covered . There's a lot of research on accuracy of referee call .

There's a lot of , or a fair bit of , research on overall referee metrics regarding distance , regarding number of calls , regarding top speed , but there isn't a lot on individual referee performance . Right , if we're talking about let's bring in a referee and let's see where their fitness is .

Outside of those advancements exams that FIFA has created to theoretically judge referee performance , there isn't a lot of research on how these referees actually do and put through a battery of performance tests . So that's where I took mine . The other aspect of it that I wanted to dig into is a lot of those studies . Look specifically at the center referee .

They're the guy at the center of the pitch . Most calls defer to him . The idea is he is the most important referee on any given team . So for me I'm like , hey , let's take a step back from that center referee . Let's look at the other guys on the pitch .

Now , as interesting as it would be to look at the performances of a VAR in the box , I don't know that it'd be that interesting . So I took the assistant referees and I said let's look at some performance metrics . I wanted to look at specifically if we take those FIFA tests and we say how well do these correlate with regard to their action ?

How well do they mimic on-field performance ? We'll take those assistant referees , we'll run them through a similar battery of tests and let's see how they do .

That was sad , but then I made it , made it through the sprints and I made it six , six full laps out of the 10 full laps you need to do of the 75 , 25 sprints again and I . It's so frustrating . I hate running on a track like I . I freaking hate it . If you ask me to do a 90 minute match on a field and cover five or six miles on a field .

Love it so excited . Walk off the field smiling yeah exactly . But if you ask me to do these intervals of 75 meters , 25 , 75 on a track , it's painful , pains me to no end . So debatable whether those tests actually really determine someone's ability on a pitch . I know it's specifically about fitness , but I hate that .

Okay , so you looked at again the tests that are out there and now you're trying to figure out . Okay , do they accurately measure performance ? Okay , go forth please .

As far as what it does , though , for a center referee , it is relatively accurate at determining how well do they maintain their fitness with these interval sprints . As a referee , yeah , we're going to walk around the field , play is going to shift , you're going to have to sprint the other way .

We can talk about the inaccuracy of those distances a little bit , but the fact is that test for center referees is pretty good . When it comes to the yeah , so I'm going to break it to you . It's a decent test , even if we don't like it when we talk about the other ones let's talk about . We've got the basically sprints .

It's a two-meter sprint Start to finish your time to go through either five or six times . One of the reasons I like that one is that's closer to what an assistant referee may do . We're on the sideline , we're watching play .

Occasionally there's a breakaway or a through ball is played and we have to sprint down to the corner flag so we can maintain our position with the offside line . However , we find specifically , the test doesn't quite mirror what's on field . For an assistant referee , they always have to carry a flag on the field .

It also affects their form biomechanically We'll get into that a little later , I think but also the distance that they cover varies . If we're talking FIFA's overall allowed field sizes , it can be anywhere from 90 meters long to 120 meters long . Now international matches it's 100 to 110 , but the vast majority of us aren't refereeing international matches .

So we can travel . If we go from the middle of the field to the corner flag , we can be traveling anywhere for 45 to 60 meters Meters in a sprint , especially trying to keep up with the speed of elite athletes on the field . That's a pretty big difference . So for me I'm like , let's take that 60 meters .

Let's say it's a breakaway , it's a counter , you're looting town . You've got one chance against man City , right , right , what does that distance look like ? But you've got one chance against man City , right , right , what does that distance look like ? But let's add in that game-like state of carrying a flag .

When an assistant referee has a flag right , ideally that flag is held down by their side the entire time . When we're running , every sprint study you look at has athletes running and pumping both arms . That is simply not the case for referees . This is a unique aspect of assistant referees and maybe some racket sports .

But for me , this is where I saw the opportunity . Right , this is a game-like state that our tests don't cover . But when doing previous research and this took me a bit of a research tangent when we look at sprinting mechanics , there have been a handful of studies looking at hey , if we restrict the arms entirely , what happens ?

We have athletes cross their arms over their chest or hold both arms down by their side . How does that affect running form ? That's not the case for referees . We've got one arm . Now , from a biomechanical standpoint , having a unilateral load or one-sided load or difference makes a big difference depending on the action you're performing , and that's what we did .

We said , hey , let's take some similar tests For us . We did 60 meter sprints and we said let's make these ARs hold a flag for one trial and then not hold a flag for another trial , and let's look at the differences .

The flag can't be moving , pumping with your arms . It has to be straight down the entire time . The flag can't be moving , pumping with your arms . It has to be straight down because that is a signal to the center referee that we do not have an offense , we do not have an offset offense , we don't have a foul . That's why we keep that flag straight down .

So that's why you're looking at the study . It's like you got one arm pumping , but one arm is going to be down with this flag .

Once you get to regional and national , sure , you might have them , it makes it a little easier , but at those grassroot levels we can still be talking a really high-level academy game .

You need to keep that flag down because the moment that flag pops up , either the center referee takes his attention off the play or he's going to blow his whistle and affect the play . So keeping that form down by your side is imperative , truly .

So , going back into kind of our testing methods , we ended up wanting to get guys who are going to have some good experience , so we ended up getting about subjects , their certification levels actually ranging pretty widely Everywhere , from guys who hit that minimum threshold for us it was one year of refereeing and at least 15 matches played as an assistant referee .

So it's okay , they've got the basics down . We also wanted to go up as high as we could certification level wise , so we had I want to say our highest level of experience was a regional referee with a little more than 30 years experience , and then our highest certification level level we did manage to get one research member who had FIFA certification .

It's a top level guy Going and refereeing international matches . During the breaks he referees MLS . It was great , that's awesome . So we got a pretty wide range of recruitment . When it came to the testing day , of course , as exercise scientists there are a couple of things we love to take .

We did some body composition metrics , looked at overall health and then we got onto the field . The first test we made them do was that 60 meter sprint . We had them run three sprints with the flag , three sprints without the flag , again on that left side , with that arm restricted , when they had the flag , and we attached them to what we call a 1080 sprint .

A 1080 sprint in layman's terms is like it's a big computer with a coil and a cord , and so we put a belt on the referees , we attach that cable to them and when they ran , we're able to measure the displacement of the cord .

Now for us , that gives us everything from force production to top speed , to distance travel , to acceleration metrics A lot of data and not a lot of time . So the moment we get a couple of these sprints in , we're talking . I think by the end , just on sprints , we had a little less than 4 million data points . Wow , so really good info .

We got these 24 guys through , had them run six sprints , three in each condition , and then on the back end , we would analyze that .

We also had them run six sprints , three in each condition , and then , on the back end , we would analyze that we also had them perform a second test , though as a referee , not everything we do is going to be linear , and this goes back to how well do the fifa tests really demonstrate on-field performance ? So we did the coda .

Now the coda is a an assistant referee-specific task and CODA stands for change of direction ability . Now the idea with the CODA is that you run 10 meters . Once you get to that 10-meter mark , you turn , you basically face fieldside and you shuffle laterally 8 meters back .

Once you hit that 8-meter cone , shuffle 8 meters again , hit that first start point and then sprint 10 meters back through the start line . The idea is with that test is we're seeing not just linear sprint but we also see that lateral or that side to side motion . How quickly can you change direction ?

Because , hey , a ball , someone tries to play a ball over the top , it gets blocked right on and the counter-attack begins immediately . The moment that first pass is played , people start to move . But if that ball is blocked and goes the other direction , you've got to change direction quickly .

Now for us , of course , when you do these FIFA tests for advancement , you don't hold a flag Immediately . Not game-like For us , easy opportunity let's do three trials of that normally , as you would with a FIFA test , and then let's do three trials where you have to hold a flag . Once we completed that , of course , we basically said thanks for coming .

We'll let you know what the results are , but it was during the analysis that we found a couple of interesting things . First , that flag holding very limited effect on the change of direction performance , that CODA test , and with that one we weren't doing doing as much .

We didn't use that 1080 sprint , that cable and cord , just because on that turnaround motion they would smack the cable and that would mess up any data , so we were mostly just running time trials with the coda . We did find , though , that there was no statistically significant change in time .

If you ran the coda in nine seconds , you'd probably run something similar to that with the flag .

it . While we didn't find statistics significant , there were a number of people who actually completed it faster while holding the flag , the thought there is it's game state-like . This is what they practice every time they go out on a field , so this is something their body is accustomed to . But also that the flag and holding it down by their side .

We were using a oh goodness , I don't remember the brand it was I think it was a Capelli flag like standard , you can buy it online . We measured the flag . We weighed the flag Standard issue . We think standard . You can buy it online . We measured the flag . We weighed the flag standard issue .

We think that weight of the flag holding that down by your side with proper form may be enough actually to help as a counterbalance . Wow , so as you're changing direction , keeping down might actually change , allow you to keep low and change your direction more quickly than as both arms pumping and having to slow one side of your body . That's interesting .

Again , it would need some follow-up work . We would probably have to do some filming and kinematic analysis . Yeah , but that was a weird one , going back through the results for sure .

There was only one other study done . It was done by oh and I'm going to pronounce his name wrong Minarolu . He was a Turkish researcher back in 2020 , right before COVID Did a similar study . He said let's take referees , let's have them hold a flag and see if they slow down , and he got a great sample size .

He got 94 Turkish referees who were like professional level , we taught , we're talking guys refereeing in the Turkish top flight . He published so little of that data . Like I'm saying , it was like a three page article . He took 94 referees and all he had was time data . It's like , yeah , they slowed down , cool , anything else ? Nope , that's it .

That's all we got . Hence why we wanted to repeat that , so we took that 1080 . We hence why we wanted to repeat that , so we took that 1080 . We got all this force data , this power data , this acceleration data and we said what is it that's actually changing ? When they're holding the flood ? Sure they're slowing down . There is some biomechanical change there .

Are they slower ? And what we found is the things that were affected weren't actually throughout the sprint at top speed . Once you have started running , you're a couple seconds in and you hit that top sprint speed . That's where the slowdown occurs . Power production drops overall top speed drops and that's to be expected .

The role of arms when running account for a couple of things . One they work to counterbalance the legs . One they work to counterbalance the legs . All of our force production is from the lower body and at the speed we're moving , those arms help us so that we're not going too far forward , leaning too far back , moving side to side .

They work as that counterbalance . So having an arm no longer able to work it puts a cap on that top speed .

What we did find , what was odd and which kind of counteracts some previous data , was when we looked at the acceleration phase , the first couple steps of that sprint , one arm not being available , acceleration didn't change holding a flag or not holding a flag I have a question .

Or did you do it as they were like an assistant referee , where they're perpendicular to the field I'm sorry , parallel to the sideline and then they move and change their body position as if they're perpendicular to the field , running towards the goal line ? How did you guys set up the start ?

If we implemented a second condition because we're already implementing three trials with a flag , three trials without a flag If we wanted to get truly balanced data , we're doubling the number of sprints they're doing .

Now .

Let me tell you I , I I am not the oldest guy in that room at almost 50 years old . I'm like middle of the pack , if not on the younger side . Let me tell I am definitely have anxiety about somehow finishing in like that lower quartile , lower third . I was like that can't be me .

But for us , this basically tells us a couple of things . Going off the top again , holding that flag decreases your top speed . You should train for it , right . In the end we are exercise scientists . Our goal is , if not clinical , it's about improving human performance .

That's where I go right , my specialty being the biomechanics , the bioenergetics and human performance . If we see a decrease in your top speed , how can we create a scenario or a training program mimics that , so that when you get to the field , even if there is that decrease from holding a flag , we minimize it ? Of course we're affecting that form biomechanically .

It's going to be impossible to eliminate it entirely . It's simply not a natural form . While we didn't have enough data really to say , hey , there's a significant change in the difference seen in a grassroots referee versus the FIFA , our one FIFA guy . It's hard to say really if , having that many years of experience , that flag effect is mitigated .

It would just require more data really to go through and differentiate between years of experience or certification level . But for us it says there are things we can do . There are things within training programs , basic training data , that we can provide early on right Grassroots referees , regional referees , to try and mitigate that speed difference early .

For an assistant referee . The accuracy of our calls specifically is entirely based on how close we are to that offside line . Primary role is to keep up with the offside line and make that offside call . We can assist the primary , the center referee , with the other calls if our positioning is good . But those offside calls we cannot get wrong .

We have to be there for that .

How willing are you to run at top speed and can you run at top speed to get down there on the line and see if that ball is in or out or has gone over the goal line or not ? That is absolutely a key match decision , as much as it is an offside being a key match decision .

They're not as common as offside , but it is a key match decision , so that is a big deal .

Second game I ever refed it was a U17 game , so higher than ready for it regardless , and I was . Ar2 .

I gotta get back into position . As I stop , I'm close to the corner flag . As I start to go the other direction , player chips the goalkeeper to the top , hits the crossbar of the line and bounces out and it's over the line . It's over the line . Meanwhile I'm , you know , beckoning the center over .

He's coming to see if it was over the line and I'm like I don't know how I was there , but I was on the corner trying to go in the other direction . That did not go in , but it goes back to the importance of it . If I weren't there I would have had no clue whatsoever In my pregame speech to every referee .

I have so many examples in my career where we had goal line decisions , so I'm thrilled that you were there . Great job being there , without a doubt , wonderful job , cool , all right . So now we've got this knowledge that we can change our training to potentially adjust for this lack of top speed that you have when you have the flag down .

So now , where does this go from here ? What's the future Now that you've done this study ? You've determined okay , I don't have an acceleration issue , but we definitely need to be training for how to adjust for top speed for assistant referees and what that might mean for their quality on the field . What's next ? Where do you go from here ?

Specifically so for us that means hey , when you're training , if you're training and it mirrors what you're going to do in game say you're doing shuttle sprints running back and forth you're training and it mirrors what you're going to do in game say you're doing shuttle sprints running back and forth , you're going for time .

You're just doing it for X number of laps or X amount of time On one of those sprints , have a flag right . The more you implement that condition , the more your body adjusts to it and the better that you will be . In the long run , you'll decrease its overall effect .

If we really want to see the magnitude of that training effect , that's another study for another day . The fact is , and that's really what we try to preach , it's you're a referee , no matter what level you are . If you're a grassroots , you could still be going up to U19 Academy . These are college level athletes and they're going hard .

If you want to keep up with them , your fitness has to be at a point where you can maintain that speed . You don't have to , you don't have to be able to be on the field right , but you have to keep up with them . So for us it's like we started working with a handful of people who are either grassroots or regionals and looking for advancement .

Professor Hewitt and I , we started to try and work with them , say , hey , let's implement a little bit of training into your regular regimen . That's going to support your referee activity , if not every day , adding those shuttle sprints , it's adding in distance and for me , of course , it's grab your flag when you go out .

The biggest problem and I think you guys you actually had a conversation with us a few weeks back on a podcast you posted about the level of training that we received as referees In most areas , at least in Atlanta , when we first become a referee you get it's a four hour intro course on the field .

Right , we are athletes too and we need to be trained as such . So for us , it's just as much as add in that flag Next time you're running on the field , next time you're doing some training , find time to work right , find time to work out , to exercise .

And the fact is , if you need assistance in creating that regimen , in creating that program , talk to some of the referees . Wherever you go , there are always going to be referees who either used to play or are pushing for advancement , who are going to be training regularly . Most of those people know what to do to some extent .

The more we can train these younger referees to one , be fit enough to play , but then two , be confident when they're on the field , the more likely they are one not to drop out because that's an issue as well but also perform better . Right , we can't . It's one thing for the parents , the spectators . They're berating us , which is truly absurd .

Come on down , give it a shot . But at the same time , if we feel better about our own performance on the field , we will do better , and the first thing we can do is be fit enough to do that before we even look at the calls .

There's an organization called Scorch Fitness which is actually the uncles Ted and Christina uncle are part owners and they actually have developed a distance-based , app-based training program specifically for soccer referees , which I find to be phenomenal . It's fantastic .

There's also another gentleman his name is Austin I'm drawing a blank on his last name who runs the Running Ref Program , which is a program that they do in person but also online as well , and they've got phenomenal resources and actually it's so funny that you're saying this .

So I I have a normal workouts that I do at the gym or at my house , but I literally just this week was like season's coming up in a couple of weeks . I should probably .

I use the ref six app and I love getting the heat maps on that and I was thinking to myself I might go to a field and just run on a field and go corner to corner and do some sprints there , do some shuttles side to side , shuffling across the penalty area back and forth , and go into sprints again and then look at my workout afterwards and see how well

it looks compared to what I would normally do in a match , to see if I'm getting myself match fit for all those things you're talking about , those changes of direction , those side toto-side movements , that constant movement that you have to do , but also that top speed that you need to be able to get up down the pitch to be in the proper position for those

counterattacks , for those key match decisions , and I think that's so important . If you are again , if you fail to plan , you will plan to fail , and as soccer referees , we need to be just like the players are doing those game-like scenarios to be able to perform on the pitch .

We also , as referees , need to be doing those game-like scenarios so that we can perform on the pitch as well .

I just want to say thank you so much for coming on and sharing your knowledge and investing time to understand the performance of referees , and I'm sure everyone has learned from this and other people might be inspired to do some additional research building on the work you've done . So thank you so much .