Everyone knows that Brazil is the country that has won the most World Cups to date.
There are five titles and generations of football legends, which have consolidated Brazil’s reputation as an eternal favorite, at every World Cup start, every four years.
But, after the disappointment of the last five tournaments, the Brazilian team turned to technology to try to come out with an advantage in 2026.
Behind the scenes of preparations, sports scientists have been tracking their athletes using wearable technology to monitor everything from their speed and heart rate to fatigue levels and recovery from injuries.
The objective is one: to provide the national team coach, Carlo Ancelotti, and his team with as much information as possible to help make decisions that could define Brazil’s fate in the World Cup.
Brazil’s debut against Morocco is approaching. And here we show how the data collected helps the team prepare for this moment.
Wearable vests
Most Brazilian professional players use “smart vests”, equipped with sensors. They look more like a sports bra, worn under a shirt.
Players wear the vests in training and in matches played for their clubs throughout the season. They generate detailed data about your movement, your performance and your recovery from injuries, if applicable.
This technology has undergone rapid advances in the last decade and the majority of teams competing in the World Cup use the same electronic performance tracking systems.
But Brazil has extensively integrated player monitoring into its men’s, women’s and lower-category teams.
Information collected by individual clubs about their athletes is relayed to the national team’s sports science department.
The data allows coaches to monitor their players throughout the season as they prepare for their international appearances.
“Every day, when we are not with the players, we communicate with the clubs and they send us information from the tracking system about the players”, explains the team’s physiologist and sports scientist, Guilherme Passos.
“So it’s easy to integrate them into our database and analyze players when they’re not with us.”
As many of the monitored athletes play abroad, this procedure helps overcome a unique challenge.
Unlike club coaches, the technical team of national teams spends little time with their stars, as many of them compete in different championships, even on other continents.
Therefore, it is very difficult to compare the performance of each one and evaluate the talents needed to form a team with the potential to win the World Cup.
But monitoring technology allows the Brazilian technical team to efficiently track athletes, even if they are thousands of kilometers away.
“We know exactly where the players are in this transition process”, explains Passos.
This visibility is an advantage when preparing for major tournaments.
Players’ choice
The choice and definition of players, their positions and tactical roles are largely defined based on data collected throughout the year.
Some players also arrive with injuries or returning from rehabilitation programs. Others may experience workloads that are too high at their clubs.
One of the most important applications of these monitoring systems involves monitoring recovery from thigh muscle injuries, a common problem in elite football.
By monitoring data such as the power and performance of players at high speed, sports scientists can assess whether a player can safely recover from possible injuries, explains Passos.
“In the case of a high-speed player, it is very important to follow this assessment”, according to the physiologist. “These are small measures to ensure complete recovery of the muscle.”
Data can also influence tactical decisions.
A particularly fast player may play well on the wing, for example. And recovery assessments can help decide whether a particular athlete should start a game or come on later in the game.
“If you have a very fast player, the coach might think about using him in a style that favors counterattacks”, explains Passos.
The issue is not just one of preparation. Smart vests will continue to be used throughout the World Cup, providing live data during games, typically held just a few days apart.
Monitoring athletes’ fatigue and recovery will help the coaching team identify who is ready to play in the next match and who will need to rest a little longer.
Testing the technology in Boston
We were filming in the US for a BBC TV series that showcased the cutting-edge technology used by professional football players across stadiums and fans at the World Cup.
Presenter Paul Carter was invited to test a smart vest made by sports technology company Catapult. The company works with several teams competing in this year’s World Cup, including Brazil.
The vest is lightweight and contains electrodes that monitor the heartbeat inside its seams, as well as a GPS device inside a pocket.
To evaluate her performance, Carter carried out training with the Boston Legacy team, which competes in the National Women’s Soccer League (NWSL), the main American women’s soccer championship.
After a series of exercises and sprintsthe technicians analyzed their performance. When heartbeats reached 177 per minute, his results were very modest.
Most surprising was the assessment known as “player load.” She reveals how much physical stress he generated during training.
Compared to an elite player, Carter produced much more carry per distance covered. In other words, he expended much more effort and moved much less efficiently.
A possible professional career for our presenter, without a shadow of a doubt, is out of the question.
For Boston Legacy director of health and performance Dan Jones, monitoring helps the coaching staff push their players to the limit during training, while protecting them from injury.
“There are moments in training when we notice that we are achieving less volume or physical condition than planned,” he explains. In these cases, the sports science team may discreetly recommend extending a workout to achieve the desired results.
In a recent game, Boston Legacy was monitoring a player who was returning from injury.
The technical team calculated a high-speed activity limit that was safe for your rehabilitation program. And their numbers were evaluated in real time, throughout the match.
“When it reached the limit, we alerted the technicians that we should think about a replacement soon”, says the technician. “We took her off the field.”
The decision is up to the technicians
Football is increasingly dependent on technology. But one of the main misconceptions about modern analytical methods is that more data automatically generates better decisions.
The reality is much more complex. Guilherme Passos mentions an example that remains in his memory.
Using tracking data, he identified a player who only ran about 6km during his matches. Many of his teammates ran approximately twice that distance.
Simply looking at the numbers, that player seemed to be underperforming. But when technicians reviewed the images, they discovered something completely different.
“That specific player was always in the right spot, in the perfect tactical position”, explains Passos. “He was a very efficient player.”
He keeps the player’s identity secret, so as not to reveal crucial tactical information just before the World Cup.
Sports scientists increasingly emphasize this lesson: football is not athletics. Running more does not necessarily mean playing better.
A player with excellent physical ratings may still be the wrong choice for a specific tactical system. Excellence in positioning, decision-making or leadership can be qualities that define a player’s career.
And it is also necessary to consider the psychology of the game.
“Sometimes we can be surprised by very good data about a player’s physical performance,” continues Passos.
“But the coach may decide not to call him up because he doesn’t believe that he, technically and mentally, can perform well in his style of play.”
Player performance analysis tools and artificial intelligence continue to be developed. As a result, the amount of information available to coaches will only increase.
At the 2026 World Cup, the AI-powered football assistant developed by FIFA and Lenovo also helps provide immediate feedback to national team coaches and players.
Known as Football AI Pro, it analyzes millions of data points using machine learning and natural language processing.
But, despite the technological revolution in football, the Brazilian technical team believes that the decisive factor is still the same: human judgment.
“Those who make the main difference are the specialized people behind the technology, who analyze the data and translate it into practical decisions”, explains Passos.
For the most successful country in world football, smart technology can help its coach put what he believes is his best team on the World Cup pitches.
But what will decide who wins will continue to be the performance of the players on the field.
Read the original version of this report (in English) on the website BBC Technology.
