Fever pitch: the science of the Football World Cup

10:13Tom Brownlee:Daily monitoring is something which has increased massively over the last 10-15 years. Now it will take lots of different forms so you will see them wearing the what looks like a sports bra during training that will be looking at their heart rate they'll be wearing a gps unit between their shoulder blades allowing the coaches to understand exactly how much distance they've covered how much of that has been at high speed the twisting and turning has more impact on your muscles and joints for example whereas the distance as a whole affects your your heart and lungs differently so that's the kind of movement analysis I suppose but they track way more than that they will do questionnaires when they wake every day how did you sleep does anywhere hurt how up for training are you today they will also be screened by the physios to see if they've got any strains or anything like that they will then also have performance testing which they won't do necessarily every single day but they might do jump testing and that allows us to understand neuromuscularly so how their nerves and their muscles are kind of firing and that's not necessarily to say oh you're not training today or you're not playing today but it's to allow that training or match minutes to be optimized

11:21Alex Grantham:so they can get the best out of them do we know how to interpret all this digital data though because for instance if you had just gps data showing movement around a pitch a goalkeeper's going to look like they haven't gone anywhere versus someone who's a midfielder has been everywhere you know so do we actually understand a how to interpret the data and do we understand how to relate it to an individual player because different people are going to have different physiologies they're going to have different strengths they're going to have different capacities to take this kind of treatment and some are going to fare better than others so do we have a sort of standard set of data for a player and therefore we know when they're operating inside their comfort zone and when things are slipping when this kind of data analysis started

12:00Tom Brownlee:sort of 10 or 15 years ago it was quite standardized because we didn't really have much more that we can use thankfully now it's become a lot more individualized for the reasons that you speak about, the positional demands are so different, even the role specific to the position that you play or how the manager wants you to play. It's much more individualised now and we've been able to become much more specific in how we look at those numbers.

12:22Alex Grantham:Are there numbers that are giveaways that a person is in the sweet spot for they're as fit as they can be, they're as ready as they can be, they're as well nourished as they can be? Are those sorts of things being looked at and is that the sort of thing that people are seeking to optimise? And can you also tell when someone is slipping a bit, you think, hmm, we need to help them in a particular area or rest them up a bit. Are people responding to data in that sort of way now with their players?

12:48Tom Brownlee:One of the key GPS metrics is something we call high speed running, which isn't necessarily a sprint, but it's quite a fast jog. So we would have an understanding of what would be typical for a player in a training session of a certain type. So if what you would expect is kind of a sort of plateau, if that does start to dip off, it might be something that you might want to look into. It's deviations, it's changes away from that average where you might start to think, oh, maybe we should just keep an eye on this person. And thankfully, there is a real blend of art and science at the top level. It's not the tail wagging the dog.

13:21Tom Brownlee:It's not someone with a white coat saying their number isn't right. Then they're not playing. But it allows a collage to be built around that individual. So it might just be having a word with them and saying, you feeling all right today? Oh, actually, I didn't sleep very well last night. My roommate snores all night. And, you know, it's little things sometimes. It doesn't have to be the baby out with the bathwater. But it can be difficult in tournament football, right? Because you also want your best 11 on the pitch. So maybe you think, look, I don't think they're quite right. So they're only going to get a half today.

13:49Tom Brownlee:That's where that coaching eye comes in. Because, you know, we're playing at the highest level here, aren't we? You want your best team out there.

13:55Alex Grantham:Tom Brownlee on how we keep our players in tip-top condition.

14:25Alex Grantham:Podcast with me, Chris Smith, and today, the science that's driving this summer's FIFA World Cup in the US, Mexico and Canada. Now, so far, we've looked at the science behind the balls and the players, and in a moment, we'll hear how a new AI-based system could turn the game totally upside down. But first, to another critical component of any match, and that's the fans. These diehard supporters are often referred to as the team's 12th man. They're almost an extra player that can help to propel aside to victory, intimidate the opposition playing away or lift a flagging performance. But can a bit of passionate support really make a difference or is it just hot air?

15:05Gill Cook:So I'm Dr Gillian Cook. I'm a senior lecturer in sport and performance psychology at Liverpool John Moores University. and I also work as a sports psychologist with a variety of Olympic Commonwealth and professional teams, including a Scottish Premiership football team. And my research predominantly looks at why some athletes can perform with excellence under pressure and others wilt under pressure, and then what it is that managers can do to create the conditions for athletes to thrive under pressure.

15:40Alex Grantham:A lot of performers say that the crowd's energy gives them energy. I remember interviewing a musician, a very famous musician, and he said to me that the crowd make us play the way we play.

15:51Gill Cook:When you've got a crowd, you have energy that comes from it. And what happens is you've got something called emotional contagion. So our emotions become contagious. And if the crowd is particularly rowdy, they're particularly amped up, that then gives that same emotion, that same arousal or energy to the players. and they then also play with more motivation, more effort. And usually the more effort players play with, the better the result tends to be. But it can also sometimes go the opposite way. Sometimes fans can make players become very self-conscious because they don't want to let them down and they start to get what's called a fear of failure.

16:37Alex Grantham:So there must be two elements of sort of training a player base for this because you've got to help people to have that and harness that winner effect. When things are going well, the crowd are with you, it's going to bolster your performance, but then be able to zone that out completely and be really focused on what you're doing when you're doing something specialist like a penalty.

16:58Gill Cook:We are stressed when we don't think we have the resources to match the demands. So the demands of the situation being, is there a threat to our ego? Do we think we'll win? Is there uncertainty? And our resources to cope are things such as do we have confidence that we're going to do well? Have we done well before? Do we do well against this particular team? And if we think we are going to do well, then having a crowd really boosts performance. And when you're playing with more confidence, that then clearly then creates a better performance outcome. And if you feel like you're in more control of the situation, so it's our fans, we can control what they do.

17:41Gill Cook:Again, that enhances performance. And finally, if you see the crowd as how good can we be? What's the possibility? How fun, how great can we create this atmosphere? That helps you to perform even better. The flip side in sport is what we call choking. So it's when you've got very good players that you expect should perform very well, but they don't. And that's when they really start to overthink and get into their own head. Instead of thinking of the possibility, what could go well? How good could this be? How many goals could we win by? They start thinking, I don't want to lose.

18:23Alex Grantham:Is a negative crowd always a bad thing, though? Can that sometimes work to your advantage because you think, well, I'm going to show them, especially if it's an away crowd and you expect them to be anti your side? can that sometimes actually, rather than diminish a player's standing in their own self-worth, can that actually help them to make reverse psychology kick in?

18:44Gill Cook:It absolutely can. So we can see that from a motivational perspective. One of the biggest forms of motivation that humans can have is either a sense of injustice or trying to prove people wrong. And we can see that when a crowd is particularly hostile, that players can then boost in their effort. So it's like a U-shaped curve then.

19:06Alex Grantham:So you can have sort of, if the crowd are hostile, you can play really well because you want to prove them wrong. If they're really for you, you play well because you want to go with them. But there's a sort of a dodgy spot in the middle where it could go either way.

19:18Gill Cook:There's sort of that optimal in the middle and you don't want too much or too little of something because you can also get over aroused. You can try too hard. You make tackles that are too strong and you end up getting sent off. But equally, as you say, and we saw this during COVID, that one of the biggest things that we can see in sport from an awful lot of research is there is a home advantage. Teams do win more at home when they have their supporters, they're in the familiar space. And that disappeared in COVID. COVID was the perfect natural experiment where you got rid of the crowd. And it was thought to have happened for two reasons.

20:01Gill Cook:One, the emotional contagion of the crowd, that then disappeared. So players' motivation from those external sources were really reduced. That extra energy that you might need in the 83rd minute was reduced. But it also had an effect on the referee. We know that from an awful lot of research that referees are more likely to give more yellow cards to the away team. Now, why is that? Well, firstly, referees are working in an imperfect environment. They don't have all the information they need. And so some of the time they will use the noise of a crowd to gauge whether a foul is particularly bad.

20:47Gill Cook:The louder the noise, the worse that foul is likely to be. Now, that clearly isn't always the case, but referees do sometimes use that as a cue to work out, OK, that's a particularly loud noise. I will therefore give a card. And there's also a motivational element, particularly when a crowd is closer to the pitch. We can find that referees give more cards to the away team and also more favourable decisions towards the home team. One can be a motivational reason that you don't want to disappoint and you can also be intimidated by a crowd.

21:26Alex Grantham:we've talked very much about sounds when you're a player on the pitch and you see this vast sea of fans the visual must have a huge psychological effect as well especially given how prominent the sense of vision is to a human brain but does the fact that the fans tend to dress in team colors does that make a difference as well so players are basically seeing a sea of red or a sea of blue because we know that color does appear to influence how we think i mean lots of studies have shown that?

21:56Gill Cook:Yes it does so we we know from research that the colour red makes you think of aggression and dominance and there's research that shows there was a research study that looked at the Olympic Games in 2004 looked at boxing and boxers were assigned red or blue at random and it was found that the boxers that boxed in red were more likely to win than those in blue and there was a statistically significant effect which shouldn't be the case if the boxers were just assigned colours at random. So why is that? So when you're playing in red as they say you're feeling dominant but from an opponent's perspective you see red, you see threat and we see that in nature all the time.

22:48Gill Cook:With the, as you say, with the fans, when they're wearing big blocks of colour, firstly, they stand out. Think of the Dutch national team. They're all in orange. Firstly, it's a colour that takes your attention. So it's distracting, can be distracting in a bad way for the players that are playing the Dutch national team. Seeing a huge block of colour is also intimidating so it can take your your focus and that can then help and boost your performance if you're seeing a huge block of orange and a sea of orange that can then help you think if you're a dutch player i have the the crowd behind me the support is willing us on to win let's win for our families the supporters and for our nation jillian cook at liverpool john moores university

23:37Alex Grantham:Now finally today, one of the things that teams invest the most amount of money in is player recruitment. So how might AI help us to build the best possible team? Jan Wint is the CEO of Player, P-L-A-I-E-R, which is an AI-powered scouting platform which scans, analyzes and aggregates the latest available data on players and with staggering accuracy.

24:02Rachael Ralph:Player came up as a coincidence because we've developed a very, very powerful AI and no one was giving us data. So we bought football data and the outcome was totally surprising. We were able and we are able to measure a football player's performance very precisely. And out of that, we can derive the squad strength, the squad strength needed to win a championship. And then we can also measure the coach's performance, which is another variable in the game.

24:27Alex Grantham:When you say data, what data do you train your AI system on?

24:34Rachael Ralph:The football player is probably the best tracked employee the world has ever seen, apart from astronauts and pilots. So there is an enormous amount of data for a football player. There are different types of data. What we are using is the foundation of any football data. It's event data, which basically measures the actions of a player on the pitch.

24:52Alex Grantham:How do you track a player around a pitch?

24:55Rachael Ralph:Well, the data providers, they put a scale on the field and a timestamp, and then they have about 150 in average per position metrics, which they write down or a computer detects it and puts it into a kind of Excel list, which is 150 metrics per minute per player per position.

25:13Alex Grantham:So there are computer programs breaking down any football game, and they're tracking each player all around the pitch all the time. So they know where they went, when, how many touches on the ball, who they were near when they were playing in certain positions or executing certain moves and so on.

25:29Rachael Ralph:Exactly. And it goes even beyond that. In England, in Premier League, you even have mesh data, which are 50 virtual body points, so you can measure any arm movement, leg movement, head movement within these already named parameters.

25:43Alex Grantham:That's extraordinary. So you literally have what a player has done on a minute-by-minute or second-by-second analysis across a game. Totally crazy, yeah. Over how many years have you got this data? For the last 14 years. Goodness. And so your system now, it ingests all that data. So what sorts of questions can you ask of it then?

26:06Rachael Ralph:How does a single player impact the success of a team? That's the core question.

26:10Alex Grantham:But the number of degrees of freedom must be huge because certain players are going to play in different positions, they're going to play in different teams, they're going to play with different teammates, and they're going to play against different teams and so surely all of those degrees of freedom there must be enormous uncertainties

26:28Rachael Ralph:No, it's actually we've reached an enormous level of accuracy so in transfer decisions we have reached 90 % accuracy so nine out of transfers are exactly as we predict them but even more than that out of these player scores which we've developed we can even derive the squad strength you need to be successful in the following season So it goes beyond just having a look at the single player.

26:52Alex Grantham:Does this mean then that if a manager comes to you, they can say, well, this is the lineup I'm thinking of putting on the pitch, these individuals, and these are the positions I'm thinking of deploying them into. Can you sort of gamify that for me? Or do you turn it around and do you say to them, well, if you put this person with this set of teammates in these positions, this is your sweet spot?

27:16Rachael Ralph:Both ways are possible. So the first part is you give us a squad and best 11 or a lineup and we can tell you exactly what the outcome will look like because obviously it depends on the opponents and on the league you're playing in. And the second part is if you turn this around, we can give you a very, very clear advice if the players you have selected on your short list or long list or which you are up to transfer, how these players will perform in your team in the following season.

27:43Alex Grantham:When I was little, I used to love football manager type computer games. And it was really easy, wasn't it? Because it told you if you bought this player, they were really good as a striker. They were rubbish in defence. And you effectively have got that then. If you've got this way of assigning parameters to players, you effectively can do what those footy manager programmes of the 1980s were doing.

28:05Rachael Ralph:Exactly. It's a little bit like when you watch old James Bond movies, all the stuff they were using, trackers and all this stuff, is now on a mobile phone. And this football example or the football game example is the same. The future is there now.

28:20Alex Grantham:Does this mean, though, that if you analyse a player, you can spot where their weaknesses are? And so then you can say, well, this is what you need to work on. When this happens, you tend to do this. A bit like with a car racing, you could look at when a certain set of manoeuvres is executed, this is where it tends to go wrong. Can you do that and help players to up their game?

28:40Rachael Ralph:That is an interesting question. We don't know, to be really honest, because we haven't come that far. We are in step one of the game still, which means we still have to persuade clubs to use us more as a validation tool in this very first phase of AI usage in football. Now, in a second step, that will be interesting to see if you can work on your strengths and weaknesses. This is something we have to figure out.

29:07Alex Grantham:one way to validate platforms like this is that you train it on a set of data from previous years and then you get it to make predictions about a year that you do have the data for but it hasn't seen it yet to see if it agrees with what actually happened so if you do that how good is your system 91 accuracy on transfers and on what does that mean what do you mean by an accuracy on a transfer

29:33Rachael Ralph:Okay, so right now the accuracy of a transfer, like if a player really makes an impact, a positive impact in the team, right now as an average figure is about 40%. So 40 % of all the transfers work the way the human responsible was planning it to happen. And we bring it up to 91%. So almost every transfer works as predicted. and on a league prediction on the bigger leagues or the for example the top five leagues in Europe we are in the prediction of the season results we are plus minus one rank and plus minus four points precise as of today but now obviously we're getting better and better so that's the you know as of today and this accuracy will go up in the years to come.

30:20Alex Grantham:Who do you think then are going going to be the two teams in the final for the World Cup?

30:24Rachael Ralph:Oh, I think you don't really need AI for that. First of all, competitions have a different mode because the low outcome game football produces a lot of, you know, you can be the pressing team, you can have 10 expected goals. In the end, the other team scores once and win the game. So a cup competition is a different thing, but I would say the typical outcome would be among France, Argentina, Spain and England. and these are the four strongest squads and they should make it, obviously depending on the draw and all the other circumstances which we can't foresee, but that should be the semi-final.

30:59Rachael Ralph:And who's going to win? I don't know. That's really difficult because as I said, not as strong in a cup competition. In a league, the best combination wins, but in a cup competition, being lucky or being unlucky has a great impact. So my personal recommendation is France, but as I said, All four teams can make it.

31:21Alex Grantham:Jan Wentz at player. And if you're wondering, the bookies have Spain and France as favourites to lift the World Cup on the 19th of July, 2026. Although Argentina, Brazil and England all might have something to say about that. Above all, may the best team win. We'll have the latest science news stories on Friday when we'll be back, including how magnetic immune cells in the liver can drive a pigeon's homing instincts. Who would have thought it? We'll also have our usual updates, of course, on LinkedIn and on Instagram. And if you'd like to support our work, we'd be ever so grateful if you did. Head over to nakedscientist.com forward slash donate to support the show.

32:00Alex Grantham:I'm Chris Smith. Thank you for listening. And until next time, from all of us here at the Naked Scientist team, goodbye.

32:20Thank you.