It's a big change in how we approach our clothes.
Athleisure is the future.
It seems that every major retailer is trying to jump on the movement that was once thought as just a passing trend, but is now seen as a radical shift in what Americans demand from their clothing.
"Athleisure is the new casual," Deirdre Clemente, a professor of history at the University of Nevada, Las Vegas, recently told Business Insider.
Clemente, whose research focus is on 20th-century American culture and the fashion industry, said that athleisure "perfectly fits with a variety of trends that have been culminating for a century."
Fitness and nutrition have become emphasized to greater degrees in American culture. The rise of "behind the scenes" celebrity social media accounts and reality TV shows gives the average person a greater idea of how the beautiful and famous get and keep their athletic, magazine-cover-ready bodies.
This has made athleisure — an entirely new category of clothing that some define as a "weird hybrid" of business casual and athletic wear — even more aspirational. Much of the clothing that people now consider work-appropriate incorporates sports-inspired materials like spandex, Lycra, and other synthetic fibers. It's combining two trends that have dominated American casual clothing — durability and comfort — in a versatile way.
"Styling is evolving to merge business casual and sportswear into one," Clemente said. "Durability of sportswear and the versatility of business casual — put those two things together, and who's not going to want to buy it?"
Americans are being drawn to athleisure in larger numbers every year. In 2015, while the whole of retail sales were flat for the year, sales of athletic wear were up 12%, according to Fortune.
Designers and retailers tend to echo Clemente's observations. Todd Snyder, the former head of menswear at J.Crew and the founder of his eponymous label, told Business Insider that he thinks athleisure is an "evolution" — not a trend or fad.
"Guys have changed the way they dress," Snyder said. "[Athleisure] is not going to go away for at least 10 years."
Comfort clearly matters to the modern American consumer.
"Athleisure plays to the American need for versatility and comfort in a way that neither sportswear nor business casual did," Clemente said.
While athletic wear was created for a specific use — sports or athletics, obviously — athleisure clothing could theoretically be for any use. And it's this versatility that has attracted many consumers to the category. These days, it can be worn in most offices and social situations without causing anyone to bat an eye. It's also generally more durable, with properties like wrinkle and odor resistance incorporated into its techy fibers.
"I don't think athleisure is going anywhere, honestly," Clemente said. "It'll only get bigger and more accessible to more people, and more acceptable in more environments."