Men's soccer sports bras: Why are they wearing those GPS harnesses?

In Friday’s World Cup match between South Korea and Portugal, Korean player Hwang Hee-Chan scored a crucial goal in injury time, then stripped off his shirt and paraded before screaming fans wearing what appears to be some kind of harness, or a sports bra for dudes. Indeed, watch soccer long enough, and you’ll notice that many male players wear what appear to be sports bras under their uniforms. You’ll see them as a substitute changes out of his warmups before entering a match, or as players exchange jerseys after the final whistle. Though that one researcher compared them, in importance, to wearing the right shoes, it doesn’t seem like men’s soccer players need the support. Why are men’s soccer players wearing what appear to be sports bras under their jerseys at the World Cup?

For science! Specifically, for the collection of individualized player GPS data. These harnesses—officially, they’re called “GPS tracker vests,” though there is nothing vest-like about them—contain, in a small pouch on the back, a small GPS tracking device. Team managers and trainers collect that data to learn precisely how far and how fast players have run in practice and during matches. This information can help managers make decisions about how hard to push a player, whether to let someone take a day off, and the like. Presumably, teams can also use the data to see who’s actually running a lot on the pitch and who only runs when the manager’s looking at them.

Like all big-money sports, soccer now employs endless data analysts to crunch the numbers on behavior, tactics, and fitness. Trackers register how often a player shoots with one foot or the other. Consultants assemble statistics on how often players complete their passes. Teams even use A.I. to game out certain game scenarios and see how players might respond, based on the behavior of thousands of players before them.

You can learn more about these vests on the website for Catapult Sports, a company that sells them, which includes this very convincing FAQ:

Q: Are GPS vests helpful for football players who aren’t professional athletes but just want to take their game to the next level?

Anyway, it’s nice that men’s soccer finally has an iconic undergarment moment to rival women’s soccer. As New Yorker staff writer Jay Caspian Kang tweeted Friday: