Every few years, a new diet or fitness craze sweeps across the land.

We had Jazzercise and aerobics in the ’80s and ’90s, which gave way to Zumba and Tae Bo in the early 21st century.  Spinning, yoga and crossfit soon become the exercise du jour, and now twerking classes have joined the ranks.

Twerking, a staple in black American communities since at least the early 1980s, is based on traditional waist and hip movements danced in West Africa. It went mainstream circa 2013, when Miley Cyrus decided she was going to twerk her way into adulthood and out of the Disney spotlight. Tongue wagging and non-existent booty gyrating, Cyrus enlisted the help of rappers like Juicy J, Big Sean and Wiz Khalifa – along with producer Mike Will – to create a new ‘ratchet’ persona based on black American hip-hop stereotypes, leaving Hannah Montana in the dust.

Cyrus has since walked back her love of hip-hop culture – considered by many to be cultural appropriation rather than appreciation in the first place – but her Bangerz-era twerking launched the dance form into the (white) mainstream, and now twerking is having its day in the sun as a fitness craze.

Now, dance studios and gyms are filled with women who want to learn how to twerk – and, it needs to be said, these classes are largely comprised of white women, often without much ass to speak of. Twerking is definitely a good workout, and many of these women are aiming to work out their thighs, quads and glutes. So far, so good.

There's also another aspect, though. They’re aiming to have fun, too; shaking their backsides in a way that is unfamiliar and probably a bit naughty to them. It's a similar dynamic to the women who attended pole-dancing classes in droves only a few years ago.

White women – especially white women like Cyrus, with less voluptuous body types – can enjoy twerking fitness classes as a kind of "all in good fun" workout; playing with and temporarily adopting a 'ratchet' persona and then returning to middle class respectability when they hit the gym changing rooms post-workout. The nagging stereotypes that have followed black women and girls around since slavery don't affect these white women.

So, there's a cultural double standard at play: white women whose work outs include twerking classes aren't faced with a negative stigma, but black women who twerk risk being seen as confirming a hypersexual stereotype.

It's not just the cultural double standard that grates, either: it's also the financial double standard. Predominantly white studios reap profits from the twerking fitness trend, as professional dance studios are overwhelmingly white and even black women dancers with years of professional experience are called 'too basic' to teach a twerking class in white dance studios.

Yet, on Instagram and YouTube, the ‘Queen of Twerkouts’ is a white woman named Lexy, and the so-called ‘best twerkout videos’ are led by white women. Meanwhile, there is hardly any mention in mainstream media or in the fitness world of The Twerk Team, a YouTube channel created in 2009 with over 100 million views and half a million subscribers, featuring three black women doing intense dance routines to popular rap and RnB songs.

While twerking becomes a professional fitness business, The Twerk Team hasn’t uploaded a video in over a year: the young, pierced and tattooed black women from Atlanta who grew up moving their bodies in this way aren’t exactly the types of instructors suburban soccer moms looking for a fun afternoon work out want to see teaching their classes.

So, white-owned studios can rake in the cash by offering twerking classes to their largely white clients, while the black women who created and mastered the dance are left on the financial sidelines.

It's also worth noting that, as with all cases of cultural appropriation, this isn't a two-way street: when black-owned studios such as the Chicago Multicultural Dance Center attempt to fuse more 'classical' dance styles like ballet with hip-hop, they are met with derision for ‘sullying the craft.’ Just the proximity to whiteness elevates black cultural phenomena like twerking into something legitimate; while too much association with blackness is deemed "trashy" or "ratchet" in the other direction.

It's White Supremacy 101, and it isn’t isolated to twerking, either: when Kylie Jenner wears green cornrows or upmarket Los Angeles boutiques sell shirts that say ‘On Fleek’ or ‘Bye Felicia,’ they are partaking in popular black American culture without having to deal with any of the negative associations that come along with really being black.

White women are free to wear their hair in "edgy" (read: black) styles and rock T-shirts that say ‘I wanna be Felicia: she’s always going somewhere’ because their unfamiliarity with black culture blinds them to the fact that Felicia was a crackhead who wasn’t going anywhere except the trap house down the street. The whole phenomenon brings to mind the Amandla Steinberg quote: “What if we loved black people as much as we loved black culture?”

So, this is the problem with twerking classes: white women who attend are half-heartedly and jokingly partaking in a culture they don’t understand by cherry-picking the fun and trendy parts. However, when it comes to the other less palatable realities of black life – police brutality, discrimination and lower levels of wealth, just to name a few – white women are suddenly not as keen to be black-adjacent.

We see white women distancing themselves from black culture when it becomes inconvenient all the time.Cyrus’ recent disavowal of hip-hop is a recent case in point, and Iggy Azalea can turn off her pretend Southern dialect and become nothing more than a blonde, white Australian girl (AKA safe and non-threatening) at any moment. White people in general can participate in black culture when it suits them, yet they have the privilege of retreating into the safety that not being black affords them at any moment.

When the novelty of twerking wears off as a fitness craze, white women everywhere will be able to choose different classes from their fancy studios, leaving the stigma of being a woman who twerks for black women. Meanwhile, white studio owners will have cashed in on yet another aspect of black American culture for personal gain, while the originators of that culture remain economically marginalized.

So, the next time one of these twerking classes pops up in your area, perhaps give it a pass, and consider supporting black-owned initiatives instead.

Next up: 15 fitness tips from Adi Gillespie, personal trainer to a Saudi royal.