The Technology Behind the U.S. Women’s National Team’s World Cup Victory
The United States women’s national team went into the 2015 FIFA Women’s World Cup with a chip on their shoulder, trying to avenge a heartbreaking finals loss in 2011. But eagle-eyed viewers might have also noticed the chips the women wore under their shirts as well, as Will Carroll pointed out on Twitter.
Alex Morgan is wearing some sort of monitor on her chest. Think some if not all are but clearest shot I've seen. pic.twitter.com/qOkqffYZNZ
— Will Carroll (@injuryexpert) June 30, 2015
The objects were Polar Global’s H7 heart rate sensors as suggested by this Wired article and confirmed by Polar Global. The USWNT is also listed as a client of Catapult, an Australian-based company that combines GPS and inertial measurement units (IMU) into a single sensor.
Strength and fitness coach Dawn Scott confirmed that her team uses heart rate sensors and GPS systems to monitor player performance. However, because the team does not have a formal relationship with either company, she could not discuss the specific devices she uses in detail. Nevertheless, she was still happy to answer general questions about how she and the rest of the American coaching staff used the devices.
The GPS system and heart rate monitor produce a wide range of metrics. Head coach Jill Ellis and her staff were mostly interested in measures of intensity, rather than total distance covered. Scott specifically discussed the percentage of high-speed running (running faster than 11 mph) and distance covered during high-speed running.
“For me they’re the main factors that then show how much a player’s involved in the high-intensity activities,” Scott said. “[That means] overlapping for your midfield player, making high-intensity runs into the box. For defenders, [it means] having to recover.”
But not every position calls for such high-intensity bursts. For those players, the coaching staff relies on meterage — a player’s average speed in meters per minute.
“So say a Lauren Holiday, who isn’t necessarily doing a lot of sprints when she’s in a holding midfield position, but she’s one of the ones who does the highest meterage, so for her, that is more of a marker of her work rate,” Scott said. “In one of the games where she was pushed into the attacking midfield role, she suddenly had a lot of max sprints.”
The games presented an additional set of challenges. Although this tournament marked the first time FIFA allowed players to wear monitoring devices on the pitch, FIFA retained the regulations prohibiting the use of technology on the sidelines. This prevented the coaching staff from using these systems to guide their in-game decision making.
“I don’t always see the purpose of real time [monitoring],” Scott said. “Sometimes in training we’ll take out the real time system, but for me that’s only if we want to get a certain physical output from a fitness point of view.”
Making matters more difficult, several of the stadiums in this summer’s World Cup were domed (like Montreal’s Olympic Stadium) or had large roofs overhanging the field (like Vancouver’s BC Place). This meant the team’s GPS-based systems were much less accurate during games.
“The interpretation of that data is crucial, especially when you’re giving that back to players and the coaches who are interested in that feedback,” Scott said.
Scott doesn’t rely on a single number to judge player performance, instead adjusting her expectations and the numbers she looks at based on the game plan for that particular match.
“It’s knowing your team, your opposition, it’s knowing your own players, and what their physical capabilities are as well,” Scott said. “Carli Lloyd’s numbers were very different in the first three games from the final three games when her role was very different.”
But unlike a coach for a club team, who can monitor their players’ workouts year round, Scott had the added challenge of making things as simple as possible for her players after their training session ended. That meant shelving the more complicated GPS monitors and giving each player a wrist-worn heart rate sensor to wear during training. To their credit, though, the players diligently stuck to the team’s training plan — and just as diligently sent the data back to Scott.
“The players were very good at giving us updates in terms of their heart rate loads,” Scott said. “And they also logged into an online training diary or physical monitoring system, where every single day they would log in, answer five questions about how they feel physically, and so I can then log in and see where a player’s physical state is.”
Scott traveled across the country, working with coaches for every National Women’s Soccer League (NWSL) team to come up with a plan that kept the national squad healthy without hindering their club’s chances of winning. Scott was quick to praise her NWSL counterparts for their cooperation.
“The clubs were given guidelines in terms of when we want to train, when we want the players to have a day off, and also ideally how long the training session should be with the player,” Scott said “And to be fair to the clubs, in that crucial period in the leadup to the World Cup, they stuck to the programs we sent.”
Off the field, Scott is working towards a doctorate from the University of Western Sydney. Unsurprisingly, Scott’s research focuses on the physical demands and training loads of elite female athletes, with a focus on soccer players. Scott’s research relies on the hundreds of hours of game data she has collected from USWNT athletes since 2012.
“The main focus is going to be to develop a training model, so looking at what are the physical demands of women’s football,” Scott said. “And then with that, we look at what is the training intervention is to prepare the players physically for those demands,” Scott said.
But not all Scott’s methods are quite so high-tech. During March’s Algarve Cup in Portugal, players complained about stiff necks and poor sleep. So before this summer’s Women’s World Cup, each player was given an allowance to buy their own pillow to take on the road with them. The result, Scott said, the team was better rest and improved performance.
“When I first suggested it, people looked at me like I’d gone mad,” Scott said. “But the players appreciated it, because it just meant something they had at every single hotel.”