Remember when it was considered nothing short of a scandal to wear anything other than dress slacks to work? Heaven’s forbid if someone could differentiate the outline of your derriere from the back of your calves.

A lot has changed since then, and long gone are the days when jeans in the workplace were limited to the occasional Casual Friday. It’s been nothing short of a casualization movement, starting with our enterprising friends in Silicon Valley, extending to creative agencies and now coming full circle to the corporate world where companies are hoping to find a competitive advantage in obtaining millennial talent.

The casualization movement is a major driver of changing fashion trends within the retail space, particularly the extensive popularity of wearing fitness apparel in a variety of everyday settings – including the workplace.

This style, called athleisure, is a favorite of millennials, who spend more money on it than both Baby Boomers and Generation X, according to a study by MONEY. The NPD Group also found that millennial spending on women’s leggings, which make up 45 percent of the athleisure category, rose 24 percent in the past year. As a whole, the athleisure category achieved sales of $43.6 billion during the same time span.

Having caught onto the trend, retailers are rushing to get a piece of the pie. From luxury brands such as Louis Vuitton and Tory Burch, to celebrity lines from the likes of Beyonce and Kate Hudson, athleisure brands are popping up everywhere. Unfortunately, this isn’t resulting in the desired effect (i.e., making bank) that brands are seeking. Rather, it’s leading to the exact opposite.

Many brands are being forced out of the space, even when they’ve found success in other segments of the retail apparel market. Urban Outfitters scaled back production of its athleisure line “Without Walls” just a year after introducing it due to lack of sales, although the company as a whole garnered nearly four percent revenue growth from 2015 to 2016. Contemporary clothing retailer Theory faced the same predicament and chose not to move forward with its stand-alone activewear line. Kit and Ace, the Canadian technical clothing start-up owned by Lululemon’s founding family, laid off nearly 10 percent of employees at its headquarters in February due to falling profit margins.

One brand defying the odds? SoulCycle.

A generic description of SoulCycle is a New-York based fitness company that sells 45-minute indoor cycling classes. In reality, SoulCycle is the physical manifestation of a multitude of millennial ideals.

SoulCycle is an experience; one that offers more benefit than burning a gazillion calories (although that’s definitely a perk). It’s a therapy session. It’s a get-together with friends. It’s a trip out to the nightclub (or at least the blasting pump-up music makes it seem that way). It’s an invite into a community that values health, fitness and being better than you were yesterday; a community where all of the active members wear trendy athletic gear branded with the SoulCycle logo (so much so that the company produces 14 athleisure collections every year).

This indicates that when it comes to millennials and athleisure, it’s about more than just basic style or comfort. It’s about discovering a lifestyle.

Millennial purchasers gravitate toward SoulCycle because it offers a ready-made packaged lifestyle for them to be a part of, one that contributes to their social lives and equips them with a sense of belonging. Because of this, the brand’s apparel becomes a “badge of honor,” as founder Julie Rice noted, because it is an obvious symbol of inclusion into the community. No matter where it’s worn – a work meeting, Sunday brunch, happy hour, a workout class – the apparel portrays a way of life that consumers want to identify with, and in turn, be associated with by others.

Brands that find a way to replicate SoulCycle’s model in their own way, with their own value system, will be those that find success, because a lifestyle – not just any pair of trendy leggings – is what drives millennials in developing loyalty to an athleisure brand.