Why do soccer players wear a bra?

Erling Haaland (Manchester City) wears a GPS vest to measure his performance. These systems provide information about the effort made and the physical condition. (Image: imago images/MIS)

In a few months, the 2026 World Cup will begin. Once again, all eyes will be on the matches that are sure to captivate even novices. If you are one of them, you may notice, perhaps for the first time, a bra worn by many players under their jersey. Its function is not to support the chest or relieve the back, but rather to hold the technology in place at chest level, as explained by Stefan Fröhlich, a sports traumatology specialist and team doctor for FC Zurich.

High Technology Close to the Skin

The bra is equipped with GPS sensors that record every movement of the player on the field. “These systems track his movements on the field, such as his position during the match, his speed, the duration of maximum sprint, and the duration of endurance running,” explains Dr. Fröhlich. They also allow measuring the frequency of the player’s acceleration and braking, as well as the intensity of his effort. Transmitted in real-time to coaches or analyzed after the match, the data provide a fairly accurate picture of what is happening on the field.

More Effective than a Fitness Tracker

What looks like a typical fitness tracker, like the one you might have at home, is actually specially designed for football. These bras measure both physical fitness data and more complex movements like direction changes or sprints. “However, they offer a higher degree of precision than fitness watches, allowing further exploitation of the data by the coach,” specifies the sports physician. These are crucial factors in high-level football. “When two teams are evenly matched in terms of technique, the one that excels in the maximum sprint area is often the one that wins.”

If you play amateur football, you can perfectly do without this gadget. “For most amateur athletes in team sports, this level of detail in terms of physical fitness is not necessary,” explains Stefan Fröhlich. For him, a watch or a fitness tracker is generally sufficient for practicing endurance sports (running, cycling, or cross-country skiing).

A Useful Tool for Coaches

For coaches, this data is invaluable. It allows adapting training to each player. “For players with high potential but measurable physical shortcomings, physical trainers can intervene to get the best out of them.” Football is much more physical today than it was 20 or 30 years ago. “In the past, a player with certain physical deficiencies could compensate for them with their technique or tactical sense. Today, professionals operate at such a high level that no position can afford such weaknesses,” observes the physician.

The Vests are also Worn by Hockey Players

Tracking systems are not exclusively reserved for football clubs. “They are used in all high-level team sports, where physical fitness plays a crucial role,” explains Stefan Fröhlich. This is especially the case in ice hockey or American football. “The more intense the effort required and the higher the stakes, the more this kind of technology is used. Football is the perfect example,” he adds.

“Some coaches rely more on their intuition.”

Vests equipped with GPS have become indispensable in the modern football world. But as useful as these tools are, they have their limits. As Dr. Fröhlich explains, “some coaches rely heavily on data, while others rely more on their intuition. Players gifted and creative in technical terms, but with less impressive physical data, have less chance with the former. Thanks to other qualities, they could still be a major asset to the team.” For now, teamwork, intuition, and game sense still elude any quantification.