At the 2026 Australian Open, a small technological device stole the show from the champions: what is the Whoop and why did the umpires ban it from the courts?
Carlos Alcaraz’s triumph against Novak Djokovic closed a memorable edition of the 2026 Australian Open. But in addition to the shots of champions, what caused discussion was a thin black bracelet that appeared (and then disappeared) on the wrists of the protagonists: the Whoop. Many spectators wondered why the referees forced both him and Jannik Sinner to remove the devices during matches.
Usually used by many athletes, both professional and otherwise, to monitor their physical condition, the bracelet has become one of the most popular gadgets in recent years, so much so that it can be purchased online for a few hundred euros, depending on the model. But where does it come from and, above all, how does it work?
The “physiological” origins. First of all, the Whoop was not born on tennis courts but on… squash. Its creator, Will Ahmed, an American university athlete, was looking for a way to understand if he was really improving his performance or if he was simply accumulating fatigue. Even though he had precise tables and qualified staff, he lacked a tool capable of transforming invisible physiological signals into objective and continuous data. Hence the idea of building an object that would measure not only training, but also the recovery of the body. Thus he was born Whoop, a sophisticated biometric analysis tool that is revolutionizing athletic training.
Why did the referees ban it? The rules of the Grand Slam tournaments are very strict: they prohibit the use on the court of any device capable of recording and transmitting data externally.
The goal is to prevent athletes from receiving “indirect communications” or tactical suggestions based on their vital signs during the match. Although it is banned during official matches, Whoop remains an ally of the greatest tennis players during training to optimize performance.
How it works. The device does not have a screen nor notifications so as not to distract the userbut collects data continuously, 24 hours a day. Its operation is based on advanced technology. First of all, take advantage of the Photoplethysmography (PPG): Small green LEDs illuminate capillaries under the skin to very precisely measure blood flow and heart rate. Then through the aHRV analysis monitors heart rate variability, a key indicator of whether the body is able to recover after intense exertion. It also takes advantage of apredictive algorithms: the system, in fact, cross-references movement and sleep data to calculate the “Strain” (physical load) and the “Recovery” (recovery capacity)
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A “virtual coach” on your wrist. Unlike a common smartwatch, the app connected to the bracelet acts like a trainer. It suggests how much to sleep and when it’s time to push hard or slow down to avoid injury.
It is precisely this ability to transform biological signals into tactical decisions that led chair judges to ban their use in competition.
Off the tennis court, tools like the Whoop bracelet are turning biological data into strategic decisions that can be evaluated by the player’s staff. In a professional context, however, even indirect information on the physiological state could be interpreted as external “support”. For this reason the judges preferred to exclude the device during the match, while allowing its use in training.
