This summer’s World Cup triggered a search query in the United States that says a great deal about how that country approaches football: do male soccer players wear sports bras? Google Trends places it at an all-time high, driven by millions of people watching football for the first time and unable to explain the bulge between players’ shoulder blades during training.
The answer is no. And the innocent question conceals, in reality, a story about data, bodies and a technology that arrived in women’s football before anyone stopped to ask whether the garment carrying it had been designed for them at all.
It looks like a sports bra. It is not.
Beneath the training top, many women footballers wear a short, fitted black garment with a small pocket positioned between the shoulder blades. The device sits inside it. The fabric simply keeps it still; it is the sensor that does the recording.
Total distance. Top speed. Number of sprints. Accelerations, decelerations and changes of pace. High-intensity minutes. Accumulated load.
A session stops being only what the coaching staff believe they saw. It becomes a sequence of data that allows them to compare what was planned with what actually happened on the pitch.
The vest represents one of the least visible aspects of the professionalisation of women’s football. It is also one of its contradictions: for years, women footballers received high-performance technology whilst wearing a garment that had been created for a different body.
GPS was already in Spain
In January 2020, the Hospiten Group’s own magazine documented the use of these devices at UDG Tenerife. The publication described, in its own words, a “GPS sports bra vest” that each player wore in both training sessions and official matches.
The coaching staff could monitor heart rate, distance covered, intensity, speed, sprints and accelerations. From that information they built an individual performance profile and adjusted each player’s workload accordingly. The data could be received in real time, pitch-side.
The devices were an integrated tool within a top-flight Spanish club’s daily work, not an occasional trial.
Since then, their use has extended to the national teams.
A study published in 2025 in the journal Applied Sciences analysed the Spanish senior, under-20 and under-17 women’s national teams using GPS across three World Cups: Australia and New Zealand 2023, Colombia 2024 and Dominican Republic 2024. Fifty-six outfield players took part — goalkeepers were excluded — wearing WIMU PRO devices positioned on the upper back. The authors include physical trainer Ismel Mazola and carry affiliations with the RFEF’s performance department.
The data showed that the step up from youth to senior level is not simply a matter of covering more ground. The difference grows with intensity: the senior side covered 16% more total distance than the under-17s, but 40% more at high speed and 47% more at sprint.
Elite football does not only demand running. It demands repeated explosive efforts, stops, restarts, and the capacity to sustain that rhythm across an entire competition. GPS turns that demand into something measurable.
When data overrules the eye
The device’s value does not lie in knowing who has run the furthest. A centre-back and a winger are not expected to produce the same output. A substitute who completes an intense session the day after the match cannot be compared directly to a player who started and ran ninety minutes.
Data only makes sense in context.
In a case study published by KINEXON, Eibar’s women’s team physical trainer, Ismel Mazola, explained that GPS served to check whether the planned loads were being met during specific sessions. The team could receive live information and use it to confirm — or challenge — what the coaching staff had perceived with their own eyes.
Mazola also noted that the data helped support decisions about line-ups. The players, for their part, showed interest in receiving personalised weekly reports of their training and match data.
Technology does not replace the coaching staff. It obliges them to verify themselves.
A footballer can appear tired yet be well within her normal parameters. Another can complete a session without showing any obvious signs of fatigue and yet have accumulated a far greater load than planned. GPS neither diagnoses an injury nor predicts when one will occur. It provides a part of the information used to decide whether to increase, maintain or reduce the workload.
That also makes it possible to address one of the least visible problems within a squad: the gap between those who play and those who do not. A starter receives a physical stimulus during a match that is very difficult to replicate in training. A substitute needs to compensate for its absence afterwards. Without data, the session may be identical for everyone. With it, individualisation becomes possible.
The technology worked. The garment, not always
That the device was useful did not mean the support was comfortable.
In a 2023 article, the Barça Innovation Hub noted that traditional vests were designed following the solution developed for men’s football, and that they can be uncomfortable for some women players, who occasionally resort to wearing a double sports top to soften the discomfort. It is an observation in a piece of popular writing, not a study on a sample of players, but it is consistent with a problem that has surfaced in different contexts.
The paradox is straightforward: a technology designed to improve performance could force an athlete to train and compete with two tight layers over her chest.
Not all players have the same body, the same size or the same support needs. The unisex model solved where to place the sensor, but not necessarily how to integrate it into the clothing a woman footballer was already wearing.
Fundación Albacete offer a Spanish example of that transition. According to the company OLIVER, the team had used traditional vests for load monitoring but replaced them with a device worn in a sleeve at calf level. The supplier attributed the change to difficulties with fit and to discomfort during training and matches. The source is the company selling the alternative and should be read as such — but the problem it describes does not appear in isolation.
Another approach took a different path. In 2022, STATSports launched what they described as the first women’s sports bra designed to integrate a GPS device, developed and tested with players including Alex Morgan, Megan Rapinoe, Steph Houghton and Katie McCabe. The aim was to eliminate the superimposed unisex vest and reduce the number of layers women players had to wear.
The evolution did not involve building a female sensor. The sensor already existed. It involved accepting that how you wear it matters too.
Tracking the cycle does not mean explaining everything
Performance technology has begun to connect with more intimate information.
The system used at Eibar included, alongside the GPS devices, planning tools, wellbeing questionnaires and forms for monitoring each player’s menstrual cycle. It was not the vest collecting that data: it was fed into the same analytical environment to give the coaching staff a broader picture of each player’s state.
The possibility is useful — but also dangerous when interpreted without sufficient knowledge.
In 2025, a consensus statement led by UEFA, published in BMJ Open Sport & Exercise Medicine, concluded that the available evidence on the direct relationship between specific phases of the cycle and football performance or injury risk remains inconclusive. Tracking should not be used to assume that a player will perform less well or be more likely to get injured on particular days.
Its purpose should be something different: detecting irregularities, helping to manage symptoms, improving each player’s understanding of her own body and protecting her health.
UEFA further establishes that participation must be voluntary, that information must be managed securely, and that it may only be shared with the player’s consent. Its recommendation is still clearer on sporting decisions: menstrual tracking should not be used to judge performance or to influence squad selection or team selection.
The distinction is fundamental.
Adapting a player’s workload based on symptoms she herself communicates is not the same as limiting her participation because an application has calculated which phase of her cycle she is in. A tool can serve to listen better to the body — or to turn it into an automated prejudice.
It depends on who is using it.
Whose kilometres are they?
Every vest generates a history.
How far a player runs. At what speed. When she loses her explosive edge. How she responds after an injury. What load she can tolerate. What the differences are between her matches and her training sessions. Even what happens when she sleeps badly, feels pain or is going through particular symptoms.
That data is valuable for improving her preparation. It could also be valuable for assessing a transfer, negotiating a contract or deciding whether a player is physically ready to continue at a club.
FIFPRO holds that information obtained through tracking technologies forms part of a player’s personal data. Its Players’ Data Rights Charter — presented jointly with FIFA in 2022 — calls for players to be informed about what is collected and why, to be able to access a copy, request corrections, withdraw consent where appropriate and transfer their records from one entity to another.
Portability is not a minor detail. A player can spend years generating information about her own body and lose access to it when her contract ends. The club keeps the platform; the player changes her badge.
The vest records her kilometres. Who they belong to remains, for now, a question without a universal answer.
Measuring better
The professionalisation of women’s football also happens away from the cameras.
It is there in the sensor hidden beneath a training top. In the fitness coach comparing the load data. In the substitute who receives a different session from the starter. In the player who can consult her own data and better understand her performance.
But professionalising does not simply mean importing everything the men’s game already used.
It means checking whether the garment fits the person who has to wear it. Not confusing information with certainty. Preventing a piece of menstrual data from becoming a label. Explaining who has access to the records and what will happen to them when the player leaves the club.
For years, football was able to measure every sprint before anyone thought to ask whether the vest was comfortable.
The next step forward is not about recording more.
It is about listening better to the person wearing the sensor.
