A humorous factor occurred when Kameron Lennox revisited the music video for “Bodily,” the 1981 pop megahit by Olivia Newton-John, who died on Monday.

For a lot of the video, Ms. Newton-John bounces round a gymnasium, coaching and terrorizing out-of-shape males whereas carrying a white leotard. In true Nineteen Eighties trend, that leotard was layered over magenta leggings and underneath a robin’s-egg blue shirt, cinched with a belt and accessorized with thick socks and a sweatband.

As a Hollywood costume designer getting ready to work on the Apple TV+ aerobics dramedy additionally known as “Bodily,” starring Rose Byrne, Ms. Lennox noticed one thing she hadn’t observed when first watching the silly-sexy music video as a baby.

The white leotard was “bunching within the groin space,” mentioned Ms. Lennox, who questioned whether or not it was a leotard or one made out of a big T-shirt. “The underside type of seems to be like a diaper. It seems to be very do-it-yourself. It seems to be just like the fashions, truly, that have been about to occur.”

Due to the video, which coincided with the daybreak of MTV, “Bodily” is remembered as a type of anthem of the aerobics period — regardless of lyrics which might be actually extra about copulation than cardio. Ms. Newton-John’s ensemble, too, has develop into a sartorial image of that period — regardless of the rudimentary development of the leotard, which “undoubtedly isn’t a exercise outfit,” mentioned Ms. Lennox, who ended up taking her costume design inspiration from lesser-known aerobics instructors like Bess Motta.

In that sense, the “Bodily” ensemble can also be an early instance of athleisure, a time period initially used to explain not train clothes however informal clothes that resembled train clothes.

As Ms. Newton-John defined in a video posted to her YouTube channel in December, the video “actually helped kick off the whole health and cardio craze of the time. It was the start of the ’80s headband trend craze. I ought to have began a scarf and leg hotter firm or made health movies. Jane Fonda beat me to it.”

It’s true that nobody popularized aerobics and the ballet-inspired aesthetic of aerobics greater than Ms. Fonda, who opened a exercise studio in 1979 and printed the best-selling “Jane Fonda’s Exercise Ebook” in 1981. However “Bodily” got here shut, taking an aerosol hairspray can to a health pattern — dance train — that was already poised to gentle up the last decade. Not simply due to the dance-centric popular culture phenomena of the last decade (“Fame” in 1980, “Flashdance” in 1983,“Footloose” in 1984) however due to the re-emergence of a textile invented in 1958: Lycra, recognized generically as spandex.

Ms. Newton-John’s video “crystallized, in a brief couple of minutes in visible type, what was occurring throughout tradition, manufacturing and shopper habits,” mentioned Sonnet Stanfill, senior curator of trend on the Victoria and Albert Museum and editor of the 2013 e book “80s Trend: From Membership to Catwalk.”

Within the Nineteen Seventies, the textile business started utilizing Lycra — beforehand used as an alternative to rubber in ladies’s girdles — to create wardrobes round train. And so ladies attending lessons or watching movies from Jazzercise or Jane Fonda have been uncovered to “an entire wardrobe they might purchase to really feel nice after they have been exercising,” Ms. Stanfill mentioned, citing leotards and tights in a variety of “almost-violent coloration tones.” Operating bras had been invented and near a decade had handed since Title IX elevated the participation of ladies in sports activities — the choices felt limitless.

“The final quarter of the twentieth century within the U.S. was this type of groundswell of celebrating the advantages of train and making a wardrobe to go together with that,” she mentioned. “Oftentimes adjustments in trend are, notably for girls, linked to moments when sport has modified life-style.”

In excessive trend, the designer Azzedine Alaïa was additionally utilizing stretchy supplies for his body-conscious designs — giving ladies a brand new alternative to indicate off their toned our bodies, Ms. Stanfill continued.

Whereas the Nineteen Eighties cardio aesthetic principally feels dated at present, sure parts of that period have briefly come again into trend. Within the 2000s, earlier than the spectacular fall of American Attire’s founder, the corporate had reintroduced vibrant leotards and glossy leggings, with advertising that was extra ironic and grungy-sexy than energetic and silly-sexy.

But the usage of spandex by no means actually went away, readapting as stylish yoga pants and leggings, then shapewear-as-outerwear. “The lasting legacy is that elasticated fiber that enables the physique to maneuver and will be fairly flattering and form-fitting should you’re wanting to indicate off your determine,” Ms. Stanfill mentioned.

However as Ms. Lennox found whereas making an attempt to trace down Nineteen Eighties leotards for the present “Bodily,” a lot of the Lycra of that period “didn’t stand the check of time.” Nonetheless, the playful spirit of Ms. Newton-John’s “Bodily” continues to encourage clothes and tradition (as seen within the Apple TV+ collection or the 2020 Dua Lipa track, each of the identical title).

When Outside Voices designed its first studio assortment in 2019, it was influenced by the leotard-over-leggings look (punctuated by ballet wraps and skirts) pioneered by Ms. Newton-John and Ms. Fonda, mentioned Ty Haney, the corporate’s founder and former chief govt.

However the inspiration went deeper: Outside Voices helped popularize athleisure within the 2010s by selling motion outdoors of conventional train, favoring “doing issues” (its tagline) over doing reps, blurring the traces between gymnasium spandex and gardening spandex. Does a leotard should be a efficiency leotard, or can or not it’s one made for a wacky music video?

There was a “joyous perspective they delivered to shifting your physique,” Ms. Haney mentioned of Ms. Newton-John and Ms. Fonda. “Releasing health from efficiency!”