Millions of people around the world wear smart rings and fitness trackers to keep tabs on their sleep, workouts, heart rate and even body temperature, all in the name of better understanding their health. But at the World Cup, that same technology is being pushed to an elite level.
In a tournament where the margin between winning and losing can be razor-thin, players are not only tracking biometric data, they’re leveraging it to fine-tune recovery, manage fatigue and unlock even the smallest performance gains.
Players have been spotted training and competing with commercial devices – such as sweat patches, WHOOPs, Oura Rings and performance vests – highlighting how consumer wearables continue to reshape the science of elite sports and, in turn, influence how athletes at every level train.
‘Technology as part of the game’
Most professional athletes are looking for every percentage point of data that might help give them a competitive advantage on a world stage, said Dr. Justin Mullner, sports medicine physician at Orlando Health Jewett Orthopedic Institute, who is the head primary care sports physician for Orlando City SC in the MLS and the Orlando Pride in the NWSL.
“These data points can then be used to follow trends and help the athlete know when their sleep is suffering or when they are not recovering as well as they usually do, so that they can intervene and change behaviors to get back on track,” Mullner said in an email.
“The data set produced by the wearables is likely more than enough for the casual athlete or weekend warrior, but it is only one small piece of the puzzle used by athletes at the highest levels,” he added.
For elite athletes, Mullner said, commercial wearables are often used in tandem with other monitoring systems such as clinical examinations by athletic trainers or physicians, and blood and urine tests.
Sweat patches
Many professional soccer players started using commercial wearables long before the World Cup kicked off.
Leading up to the tournament, a high-tech “sticker” that measures sweat played a major role in helping players on the Brazilian team train and prepare.
“Earlier this year, the Gatorade Sports Science Institute worked extensively with the Brazilian national team, conducting sweat testing with players to generate personalized hydration insights, including individual sweat rate and electrolyte loss profiles,” said Roozbeh Ghaffari, CEO and co-founder of Epicore Biosystems, which partnered with Gatorade to deploy the Gx Sweat Patches.
The Gx Sweat Patch sticks to the body and works by measuring sweat rate, fluid loss, sodium concentration and sodium loss. The patches are single-use, and they connect to a smartphone app where users can monitor metrics and gain insights on hydration needs and recovery during high-intensity workouts.
“Think of it as a smart sticker. You apply it to your skin, and it contains tiny micro-channels – almost like swim lanes – that fill with very small amounts of sweat. That’s where the science happens,” Ghaffari said.
“The patch has built-in chemistry that analyzes the composition of your sweat. It measures both the sodium concentration and the amount of sweat that’s been collected,” he said. “Those two pieces of information are incredibly valuable to sports scientists because they help personalize hydration strategies for both elite athletes as well as everyday athletes.”
Fitness bands
One wearable device that some players have been sporting during World Cup matches is the WHOOP fitness band. Worn snug against the skin on the wrist, bicep or other WHOOP Body locations, it monitors health metrics including sleep, strain, stress and heart rate.
“While we don’t have a commercial partnership with any national team, many organisations and individuals choose WHOOP to help maximize their performance during such an intense competition. … England is one of those teams,” Greg Grosicki, a data scientist at WHOOP, said in an email.
“England will cross multiple time zones as they progress through the tournament,” he said, which means players may struggle with jet lag and fatigue.
Travel and sleep disruptions can have a significant impact on any athlete’s performance. Grosicki said that WHOOP data – not collected from the players but in research studies – shows that on days users log travel or jet lag, heart rate variability can drop about 9%, sleep performance may fall by up to 6 points, and sleep consistency can be up to 19% lower.
“For a squad that’s flown from the UK to North America and onwards, those numbers are meaningful,” Grosicki said.
Smart rings
Another fitness tracker hitting the World Cup stage is Oura Ring. The US Men’s team received Oura Rings through a partnership that the wearable tech brand has with US Soccer, said Doug Sweeny, Oura’s chief marketing officer.
The players are not required to wear the Oura Rings, according to US Soccer, but if they choose to do so, some of the health data could help them more closely monitor sleep patterns, skin temperature, blood oxygen, recovery and their readiness score, a metric that considers resting heart rate, heart rate variability and body temperature.
These metrics could help inform when players may benefit from more recovery before or after training and when their bodies may be primed for more intense workouts.
Officials at US Soccer said they are being “mindful” about educating athletes on how to gain insights from their devices in a healthy way, for both psychological and physical health. For instance, if a player has a bad night’s sleep before a match and their readiness score is down, that could get into their head and erode confidence. Sports scientists and coaches encourage players to not treat a single metric as a final verdict on how they will perform.
Players were previously forbidden from wearing any jewelry on the pitch, but as of Wednesday, the International Football Association Board’s Laws of the Game have loosened FIFA’s restrictions: “Accessories are permitted if they are not dangerous and if safely and securely covered.”
Performance vests
Twelve nations have been utilizing GPS tracking systems from the sports technology company STATSports throughout the World Cup, primarily in a performance vest that monitors physical data in real time, including speed, heart rate and distance.
England is using STATSports technology to provide live in-game GPS performance data at a World Cup for the first time. The system enables coaches and sports scientists to monitor player workloads and physical performance throughout the tournament.
“GPS data is measured through small units within vests that players wear. The unit is situated on the players upper back to ensure optimal signal from the military grade satellite navigation system,” Phil Keehne, director of sport science with the MLS team FC Cincinnati, who is affiliated with STATSports technology, said in an email.
By Jacqueline Howard and Andrew Quimby / CNN
