‘Data is not steroids’: Why were Jannik Sinner and Carlos Alcaraz banned from wearing fitness trackers at Australian Open?

An argument over banned “wearable” devices such as Whoop fitness trackers has erupted at the Australian Open after top players Jannik Sinner, Carlos Alcaraz and Aryna Sabalenka were ordered to remove them before their matches.

Tennis Australia, the organiser of the Australian Open, confirmed that the wearable wrist technology is not permitted at the grand slams – although it said that the tournament is “in discussions” over allowing such devices in the future.

Wearable technology is permitted on the ATP and WTA tours. When the ATP Tour announced the approval of in-match wearable devices in 2024, a statement from then chief sporting officer Ross Hutchins said the technology was a “big step forward in our push to optimise player performance and prevent injury”.

Sinner was ordered to remove a Whoop device, which was hidden underneath his wristband, before his fourth-round match against Luciano Darderi on Monday.

The previous day, Alcaraz was also stopped from wearing a Whoop device by a tournament official after it was spotted mid-match. Sabalenka had hers removed earlier in the tournament.

What are wearable fitness trackers and why are they not allowed at grand slams?

In other elite high-intensity sports, such as football and rugby union, data and fitness tracking are used to identify when players are in the “red zone” and could be more susceptible to injury without sufficient recovery.

Wearable devices such as the screenless Whoop sensor track biometric data and motion. The technology is designed to be worn on the wrist, or other supported positions, such as around the chest, during training, competition, and recovery.

According to a description of the product, the data it provides includes heart rate, heart rate variability, recovery, activity strain, blood oxygenation, skin temperature, respiratory rate and blood pressure, as well as sleep stages and performance. This data can then be synced via Bluetooth and read by a coach using a paired mobile device.

The International Tennis Federation (ITF) approved the Whoop device following a review last December as long as haptic feedback, such as vibrations on the wrist, is disabled during competition. In-match wearable technology has been approved by the WTA since 2021 and the ATP since 2024.

There are different rules at the grand slams, however, with Tennis Australia also pointing to the fact that the tournament uses high-tech cameras to provide players with data such as distance covered, changes of direction and sprints to measure load. The tournament has an existing partnership with Bolt 6, which operates the Electronic Line Calling system using ball-tracking technology.

“Wearables are currently not permitted at Grand Slams,” a Tennis Australia spokesperson said. “The Australian Open is involved in ongoing discussions on how this situation could change.”

There is an argument that elite players with greater resources could have an unfair advantage if they have access to live in-match data and their opponent does not.

Before in-match coaching was approved a few years ago (coaching is now fully embraced by the Australian Open with separate coaching pods), tennis would pride itself on the players having to work out problems for themselves once they stepped onto the court.

Why do players want to wear wearable devices during matches?

Aryna Sabalenka is a Whoop ambassador and explained how she used the technology to assist her recovery during her US Open title run in 2024. In a video published by the WTA, she explained that the Whoop band monitored her stress levels between matches and the data advised her to take days off after it found she was in the “red zone”.

Jannik Sinner, who struggled with the extreme heat during his third-round win, said he was planning to use the technology not for in-match use but to inform his recovery before the quarter-finals.

“There is certain data what we would like to track a little bit on court,” Sinner said. “It’s not for the live thing. It’s more about [what] you can see after the match. These are datas what we would like to use also in practice sessions, because from that you can practice on with the heart rate, how much calories you burn, all these kind of things.”

A Whoop spokesperson said: “Whoop believes athletes have a fundamental right to understand their own performance and health – including during competition at events like the Australian Open.

“Whoop is approved by the International Tennis Federation for in-match wear and poses no safety, fairness, or competitive risk. Blocking access to personal health data does not protect sport. Whoop will continue to stand with athletes and our members to defend their right to their data.”

After Carlos Alcaraz was caught wearing the technology under his wristband on Sunday, the Whoop founder and CEO Will Ahmed posted on X (Twitter): “Ridiculous. Whoop is approved by the International Tennis Federation for in-match wear and poses no safety risk. Let the athletes measure their bodies. Data is not steroids!”

Why did Jannik Sinner try and wear the technology if it is banned by the tournament?

This is unclear. After his fourth-round win, the defending champion said: “The umpire asked me straightaway, if this is the tracker. I said yes. He said remove. It’s fine. There are other things we could use. The vest [with tracker inside]. But it’s a bit for me uncomfortable. You feel like you have something on the shoulders. It’s a bit different. But rules are rules. I understand. I won’t use it again.”