The hashtag #doingthings has been used about a hundred and twenty-five thousand times on Instagram. That’s a little less than #kalesalad, but more than, say, #labradorpuppies. Most of the posts are connected to the clothing brand Outdoor Voices, which was founded by a graduate of the Parsons School of Design named Tyler Haney, in 2014, when she was twenty-five years old. OV makes crop tops and shorts and leggings and fleeces that are soft but well structured and come in colors like lagoon and rose quartz—the company’s advertising helped pioneer a now ubiquitous consumer aesthetic of tasteful minimalist saturation that you might call Sensual Organic Algorithm. Women’s apparel makes up eighty per cent of the company’s sales. The trademark OV look is a racerback crop top and a matching pair of high-waisted leggings, an outfit designed to shape and flatter the body, and to expose it: OV’s textured compression fabric is so snug that it borders on disciplinary, and its leggings “sculpt” the body, like Spanx. The clothes photograph beautifully—somehow, they make the wearer look as if she were put on earth to be viewed on Instagram, posing against a forest vista in flamingo-colored spandex and a smile.

Outdoor Voices is frequently described as an athleisure brand, although Haney, who was a serious athlete in her teens, hates the term, associating it with clothes that were made for watching TV while occasionally thinking about the gym. “Every product that we make is made to sweat in,” she has said. Chip Wilson, the Canadian founder of Lululemon, the company sometimes credited with creating the athleisure market, also refuses the label: in his memoir, “Little Black Stretchy Pants,” he insists that athleisure is for Diet Coke-drinking mall shoppers in New Jersey who wear pink velour, whereas the ideal Lululemon customer is a thirty-two-year-old woman named Ocean who earns six figures and has ninety minutes to work out every day. But both OV and Lululemon appeal to the desire to wear workout clothes around the clock, and Haney has succeeded in part because Wilson’s ritzy vision—picture Ocean in black leggings and a rich-mom tank top—has, for many younger women, become passé. Athleisure, in any case, means different things for different people. I tend to think of it as activewear that costs more than seems entirely sensible, or as a spandex-clad arm of the long-standing ideology that urges women to improve the market value of their physical form.

According to one research firm, the activewear market is now a fifty-five-billion-dollar industry, and accounts for nearly a quarter of all U.S. apparel sales. Outdoor Voices is only a fraction of that market, but it has raised nearly sixty million dollars from investors and has had triple-digit growth every year since its founding. (It is not yet profitable, though Haney says it’s “close.”) It is possible to imagine the brand following the same trajectory as Lululemon, or the more male-focussed Under Armour, both of which were founded in the nineties, went public in the mid-two-thousands, and now bring in billions of dollars in annual revenue. OV’s first general manager and its V.P. of community came from Lululemon; its V.P. of product came from Under Armour; its board includes Mickey Drexler, who was previously the C.E.O. of the Gap and J. Crew. In February, OV announced that Pam Catlett, a former executive at Nike and at Under Armour, had joined as the company’s president and C.O.O. Catlett, in a press release, hailed OV as “the future of the athletic wear market.”

OV’s vision of physical activity is very different from the sort usually touted by Under Armour or Nike. Rather than advertising world-class athletes engaged in rigorous training or fierce competition, OV emphasizes low-key workouts and everyday movement. The company became familiar to the fashion-conscious—and to many Manhattan commuters—in part through its tote bags, which bear the gnomic slogan “Technical Apparel for Recreation.” The idea is that, in the absence of quantified results and competitive pressure, physical activity will feel like play.

If you spend time scrolling through the most popular #doingthings photos, you’ll find a seemingly focus-grouped parade of women in colorful OV outfits hiking, doing yoga, jogging on the beach. Almost none of these women are paid by OV, but many of them use Instagram professionally, as life-style or fashion bloggers, or paraprofessionally, as millennials with phones whose well-being is loosely connected to their popularity online. A life-style blogger in Connecticut, whose uncompensated #doingthings post I had come across, lamented how much time she and her peers devoted to Instagram. “It’s a shame,” she said. “People need to wake up and realize—like, what are we really doing here? But, until then, you have to do it.” If members of the company’s marketing team spot someone posting “inspiring U.G.C.,” or user-generated content, they might invite that person to become one of OV’s hundred and fifty or so ambassadors: a noticeably diverse group of dancers and climbers and fitness coaches and vegan-recipe developers who get free clothes in exchange for posting photos of themselves wearing them.

OV also pays a small number of professional influencers to post Outdoor Voices photos on their Instagram accounts. (A spokesperson declined to specify how many.) Aside from the #OVOfficial or #OVAmbassador hashtag, it’s nearly impossible to tell one type of picture from another: F.T.C. guidelines instruct users to disclose in detail any “material connection” to a brand they’re endorsing, but these rules are frequently sidestepped. Instagram encourages all users to act as influencers, and OV fans often allow the brand to promote their freely posted #doingthings photos in ads. “Probably ninety-five per cent of the ads you see on Instagram are user-generated,” the company’s general manager told me. (She later clarified that this was a rough, and probably hyperbolic, estimate.) Nike built its identity by paying celebrity athletes millions of dollars to serve as the faces of the brand. Outdoor Voices advertises non-famous people who mostly do not get paid but whose lives, thanks to social media, are refracted through the usual mechanisms of celebrity.

#Doingthings is short for the company’s full slogan, “Doing Things Is Better Than Not Doing Things.” As a general proposition, this does not strike me as especially convincing: idleness can be wonderful, and, these days, most of us are required to do too much. But, as a guiding principle for athletic activity, the slogan is pleasantly open-ended—“Just Do It” flipped for an era of inclusivity and wellness. (The Nike slogan was inspired by the last words of the Utah murderer Gary Gilmore, who, just before he was executed, in 1977, by firing squad, said, “Let’s do it.”) The company often hires models, and features women, who have curves and generous stomachs, and who fall at the larger end of its sizing spectrum (although, to the displeasure of quite a few would-be consumers, this spectrum extends only to XL). Showing “real” women is good for business: last September, “Today” devoted an article on its Web site to an Outdoor Voices ad that featured visible cellulite on a model’s thigh; in January, OV reposted a life-style blogger’s photo of her stretch-marked postpartum torso in a gray OV set, and the post received more than fifteen thousand likes. Still, these are clothes that broadcast a commitment to disciplining your body by working out. As the writer Moira Weigel put it, in an essay about athleisure, these clothes “encourage you to produce yourself as the body that they ideally display.”