In 2022, we noted a discussion by Julia Powles and Toby Walsh, summarized here, that warned about the increasing collection of data about elite athletes. The data, they said, does not flow to the sports scientists who really can help athletes perform better and minimize their risk of injury, but to data scientists and data crunchers. The money could be better spent on healthier environments and financial support. Powles, with Jacqueline Alderson, followed up in 2023 with best practice principles.
Cue tennis. At this year’s Australian Open, which concluded on February 1, eventual men’s singles champion Carlos Alcaraz, women’s singles finalist Aryna Sabalenka, and men’s singles semifinalist Jannik Sinner were all told to remove their Whoop tracker devices before playing early-round matches.
An important part of this story is the ridiculously convoluted nature of tennis politics. The International Tennis Federation runs lower-level tournaments and junior events; the Grand Slams are laws unto themselves; the men’s and women’s pro tours are run by the ATP and WTA respectively. That’s seven powers – without the national tennis federations or the national and international anti-doping edifice.
The players were caught between conflicting decisions. In mid-December, the ITF approved Whoop devices in competition as long as haptic feedback is disabled, adding it to its list of permitted “Player Analysis Technology” devices. On a Whoop, “haptic feedback” means the device vibrates to alert you to…something.
The ITF published its detailed examination (see also a wearer’s review by Emilie Lavinia at The Independent). Whoop’s array of sensors can capture: heart rate, heart rate variability, sleep stages and performance, recovery, activity strain metrics, blood oxygenation (SpO2), skin temperature, respiratory rate, and blood pressure (only some models), and perform on-demand ECG and irregular heart rhythm notification (only some regions, where it’s approved). As the ITF notes, data capture takes place automatically whenever the athlete is wearing the device. Players are allowed to charge the device on-court using its battery pack.
So far, so good. Turning off haptic feedback requires the player to disable alarms, turn off the “Strength Trainer” screens; and turn off “Strain Target” if they want to use “Live Activity” mode. The player has to show tournament officials on request that their settings are compliant (or that they’re using the Whoop 3.0, which has no haptic feedback).
The device has no screen; viewing the data requires an Android or iOS device, the app, paired via Bluetooth, and a subscription. This is the Gillette razor, or “free puppy” business model: the device is free, you pay for ongoing access to your own data.
So basically, the ITF is allowing players to collect data using the Whoop device for future inspection and discussion with their teams, as long as it doesn’t vibrate on their wrist. The key here is the potential for the device to be a conduit for an automated form of in-match coaching; the definition of PAT devices given in Appendix III of the ITF’s Rules of Tennis (PDF) specifically directs readers to Rule 30, which covers coaching.
For most of tennis’s Open Era – basically since 1968, when the sport went professional – coaching from the stands was banned. The original argument in favor of the ban was that tennis was and is a highly unequal sport. Top players can afford any assistance they want. The lowest-ranked players scrounge, as Irish player Conor Niland, who topped out at 129 in the world, recounts in a Guardian interview and in his excellent 2024 book, The Racket. Until the 1990s, even mid-range players often toured alone. Therefore, allowing coaching from the stands during matches threatened to make the playing field even more unequal.
As money flowed into tennis, the numbers who could afford traveling coaches rose and the no-coaching rule was increasingly flouted. Following a series of trials, the WTA began allowing coaching in 2022. The ATP, the ITF, and the Grand Slams finally began allowing it in 2025. Rule 30 leaves it open for events’ governing bodies to prohibit it.
The Whoop controversy digitizes all this baggage. Rule 30 differentiates between off-court coaching (coaching from the stands), which is permitted, and on-court coaching, which is only permitted during specific team events. Ordinary watches are allowed, but smart watches and mobile phones are banned because they are capable of communications, Teresa Merklin explains at Fiend at Court.
“We have coaching. why can’t you have your own data?” former champion Todd Woodbridge asked on TV.
We are still at the beginning of these technologies and their controversies. Merklin digs up a forgotten incident: in 2013, Wimbledon shot down Bethanie Mattek-Sands’ query about wearing Google Glass. Devices will keep shrinking and becoming harder to spot.
Unlike in the past, however, PATs are cheap compared to hiring traveling personnel. While Powles and Walsh were undoubtedly right that data analysis is no substitute for physiologists’ and sports scientists’ expertise, PATs might give lower-ranked players previously unaffordable insight. Given the increasing heat stress at many tournaments, feedback that warns when your body is overstressed seems like a good idea. On the other hand, can you imagine how much bettors would love to have access to this kind of data in real time?
Wendy M. Grossman is an award-winning journalist. Her Web site has an extensive archive of her books, articles, and music, and an archive of earlier columns in this series. She is a contributing editor for the Plutopia News Network podcast. Follow on Mastodon or Bluesky.