Isn’t it crazy to think that less than four years ago, Carbon38 didn’t exist?

I mean, I can barely remember a time when leggings and sneakers weren’t considered appropriate and legitimately fashionable attire for the office (okay my, office), for dinner and drinks—for just about anywhere except the gym.

But before January 2013, when Caroline Gogolak and Katie Warner Johnson launched what was then dubbed the “Net-a-Porter of fitness fashion,” the now-booming luxury activewear market was in its infancy (and barre classes were still filled with girls in their ancient sorority tees).

The mind-bending speed of the fashion world’s evolution—one in which elastic waistbands and shoes without heels now spark Birkin-length waiting lists—hasn’t been lost on Carbon38’s founders, who have played a major role in that transformation from the very outset.

“The shift in the way we dress has been unprecedented because it’s been such a fast shift,” says Johnson. “It’s a testament to technology and how quickly ideas spread, [as well as] women’s changing role in the workplace. Everything is coming together in a perfect storm that makes Spandex so desirable. And we hit it at the right time, just before the wave was starting to build.”

Now, of course, that tsunami is pretty much unstoppable—according to NPD Group, the activewear market is worth $44 billion in the US, and Carbon38 is projected to account for $20 million of that with its 2016 sales alone (a nearly three-fold jump from the previous year).

The innovative duo is also incredibly aware of how many hot new players that have entered the fitness fashion sales space since Carbon38 launched, from Bandier and Net-a-Sporter to Fabletics and even SoulCycle with their new monthly collections.

So what’s the OG athleisure retailer doing to stay at the top of shoppers’ minds (and in cahoots with their wallets)?

Read on to get the latest on Carbon38’s foray into fashion design, its expansion into menswear and stores, and why its founders predict the power suit of the future will be made of Spandex. 

It’s been six months since Carbon38’s private label apparel collection launched—what’s the latest news on that front?
Katie Warner Johnson: Our latest collection just went live on June 30, which we’re really excited about… it’s inspired by the summer [Olympic] games. Really, what we’re emphasizing is print and performance. The prints are super energized, inspired by the Olympic rings and also the traditional Carnival costumes of Brazil—it’s beautiful, with rich tones of reds and blues and yellows.

It’s a bit of a departure from what we’ve done in the past, but our customer is always our compass; it’s what she’s asking for.

What sort of feedback have you been getting from your customer since the launch in late 2015, and how has the line evolved to meet her needs?
Caroline Gogolak: Some of the styles we launched were, for example, a dress and a blazer with the DNA of activewear, but in a ready-to-wear silhouette. Those were very bold things to put forward on our platform, and we saw a huge demand for them. So for our fashion collection, we’re introducing more ready-to-wear silhouettes but with activewear construction and fabrics.

KWJ: As women, we need clothes that we can sweat in and raise families in and run companies in. And the perfect dress that you can throw in the washer and dryer—and feel really comfortable in—is so important. So as we launch collections, you’ll see that it’ll oscillate between performance basics, like sports bras and leggings, and dresses and outerwear that push the boundaries of the category.

How frequently do you plan on releasing new collections going forward?
CG: By 2017, it’ll be monthly.

Any cool collabs on the horizon?
KWJ: We do have a designer collaboration coming up in [late] 2016, and an artist collaboration in [early] 2017. We do very few collaborations, but they’re very targeted and really speak to the Carbonistas… they’re ones we really believe in.

CG: We’re introducing sport-specific shops as well, starting with ski in November—[eventually, we also plan to launch] golf, tennis, road biking, triathlon, marathon. [Our customer] wants to explore other forms of working out besides the studio, and there have been a lot of cool brands that are for sports like golf or triathlons, that meet that fashionable customer we’re after.

And I hear you’re launching a menswear shop soon…
CG: Yes, we’re launching at the end of August. We have a lot of male investors and they’re saying ‘What about us?’ A few of our current vendors are [debuting] men’s collections, and we saw that as a signal to launch a test and see how our customer responds to it.

KWJ: Similar to how womenswear was 2-3 years ago, all these smaller, cool [men’s athleisure] brands are coming to market. I think it speaks to the fact that corporate wardrobes are changing. People are becoming more casual, performance-oriented, and healthy, and we can’t leave out the guys!

Definitely not! Also on the retail side, I know you’ve been testing out a Carbon38 shop-in-shop with Spier Pilates in Los Angeles. Are stores something you’re thinking about?
KWJ: I personally believe omnichannel retail is the way of the future, but there’s got to be a more seamless solution than the way we look at it today—with very traditional brick-and-mortar and very traditional e-commerce. I don’t think anyone has quite cracked that yet. We’re still looking at a bunch of options… But I would consider some kind of offline presence for Carbon38 inevitable.

Within the next year or so?
KWJ: Probably not, but we’ll launch some tests.

Since Carbon 38 first arrived on the scene, lots of other athleisure retailers have cropped up. How has the boom affected the brand and how are you staying ahead of the competition?
KWJ: It’s only been great for us. It’s kind of like the juice craze—Organic Avenue or Liqueteria used to be the only ones out there, but now every [town] has a juice bar. It just means more people are drinking juice.

We really just focus on that specific customer we know so well because we are the customer. We’re not just following a trend; the trend came up from behind us while we were busy creating something that was important to us. Caroline and I have been athletes our whole lives—we’re so rooted in this brand and have been able to build a community around it.

And it’s about to get even bigger—you’re in the midst of a pretty big fundraising push.
KWJ: It’s an important fundraising round for us: Our only real fundraising announcement to date. I think it speaks to the fact that we’ve been able to build such a following of customers and vendors and ambassadors who believe in the market and us.

So why do you think Carbon38 sparks all of this excitement?
CG: Retail in general is going through a huge change, ready-to-wear is going through a disruption, and we’re addressing that. We don’t see [athleisure] as a trend—we see it as a real cultural shift in the way people are dressing.

KWJ: I think we’re going to look at suits in a couple of years as thought they were corsets from the Victorian era.

Ready to shop? We don’t blame you. Check out the three tank-top styles you need for summer, the season’s must-have print, and a lesson in how to keep cool (and look cool) in harem pants.