“Before a workout, we pull on our leggings and wriggle (or shove) ourselves into a sports bra. We put on a high-performance tee, lace up our sneakers—and then forget about it all. That’s the point: You should be able to focus on your workout, not your gear.

Except when you can’t. A bra chafes, a shirt rides up, pants sag. When your workout wear doesn’t fit right, it’s the only thing you can think about.

If you’re trying to compete at an elite level, like the U.S. Women’s National Team, that distraction is the last thing you need. Their gear has to be Goldilocks good: not too big, not too small, but just right for 90-plus minutes on the pitch. Thankfully, when the USWNT takes the field in the World Cup this month, they will have some of the most technologically advanced uniforms ever made for women’s soccer, with fabrics that speed drying time and a fit based on three years of body scans and athlete feedback. “The number one thing is comfort,” says Cassie Looker, senior apparel product manager of global football for Nike. “We have data about what an elite footballer looks like: We know how much power they generate from their lower body—glutes, thighs, and hamstrings—and we really design for the body in motion.”

Short length, for example, is a key factor. “You don’t want it too short because that’s too revealing, but too long can really prohibit all that dynamic movement,” says Looker. So is the neckline opening, sleeve fit, and the length of the jersey itself (so it doesn’t ride up).

As women have been breaking barriers in sports, they’ve often had to do it in poor conditions—on injury-provoking fields or with ill-fitting or outright sexist gear—all while getting paid far less than their male counterparts. A lot of work still needs to be done to close the gap on equal pay for female athletes, but sportswear, at least, has improved dramatically.”