Flapper girls in the 1920s with their boyish silhouettes; the nipped-in waist -- Marilyn Monroe -- of the Fifties; Jane Fonda's high-rise leotards in the 1980s; a Nineties Kate Moss igniting the heroin-chic craze -- and then the arrival of Giselle Bundchen: toned and tanned; sculpted and sexy.
At the turn of the last century, Alexander McQueen famously dubbed the Brazilian 'the body' and certainly with a swish of her flowing mane and a flash of her long, bronzed limbs, she put paid to the jutting hip bones and pokey ribs that the likes of Moss had promoted a decade previously.
Indeed, watching the latest installment of the celebrated Victoria's Secret catwalk show, which took place in Manhattan last month, it seems that bones are -- thankfully -- still being banished.
There, some of the industry's most famous faces and figures -- Alessandra Ambrosio, Adriana Lima et al -- strutted down the runway confidently brandishing shapely bums and statuesque thighs. Curvy? Probably not quite, yes most of them are still a tiny size six or eight, but certainly these are women who look like they could face into a stiff breeze without keeling over.
"I think women were fed up of looking at blatantly unhealthy figures," leading Irish model Roz Lipsett (28) tells me of the catwalk industry's switch from scrawny to seductive.
"I'm not saying the Victoria's Secret girls are realistic per say, but at least they look nourished and healthy with glowing skin and a toned body."
And New York-based Dubliner Roz knows more than most about what the ultimate Victoria's Secret body entails: she's bagged a rare audition -- which she describes as "nerve-wrecking" but also a "dream" -- at the brand's Manhattan headquarters three times in the last five years.
"Even the supermodels who take part in the show every year still have to reapply, so I saw all the top girls there. I was in good company!"
Of course, we all know that trends come and go and -- whether we like it or not -- no trend would be complete without the inclusion of body-types, specifically those of women. Preferences for face shape, breast size, height, weight and ethnicity -- not to mention the prominence of your behind -- change as often as catwalk inclinations.
"The first time that people started asking me for that Victoria's Secret look was actually back in 2006," personal trainer Justin Gelband -- dubbed the "model whisperer" -- tells me from New York.
His schedule is as intense as his famously tough workouts -- indeed, he's just off a flight from Japan -- and his prices, $50 for a 40 minute group class and $250 for an hour-long one-on-one session, reflect his in-demand status with a whole host of catwalk queens of-the-moment.
"Miranda Kerr walked in the 2006 Victoria's Secret show -- and, it probably goes without saying, she looked great," Justin says, referring to the Australian runway superstar.
"But then she came to me in Los Angeles, where I was originally based, and together we transformed her body for 2007. She was the stand-out Angel of that year and after that my career really took off."
Now, I would have assumed, like most people I suspect, that Miranda Kerr has always looked pretty close to perfection: she's 5ft 9in, a minuscule size 6 and boasts a -- gulp! -- 24-inch waist. But after my conversation with Justin, I'm intrigued. So I compare her 2006 body to the shape she sported a year later: not to start nit-picking, but there's certainly a difference. The latter Miranda is leaner and meaner; it's not difficult to see why Justin became an overnight success.
"It's easy to assume that these women are just genetically gifted," Justin adds. "But while it's certainly a gift for them to be tall, the rest comes down to hard work and dedication to looking good."
Models come to him -- as well as Miranda, he's worked with the likes of Rosie Huntington Whitely, Candice Swanepoel and Irina Shayk -- because he can make even the slimmest bodies more toned, leaner and fitter. He targets smaller muscle groups, think ankles, knees and elbows, and always works on core strength and good posture.
But what about those of us who aren't quite supermodels, but still want to channel a little bit of our inner Angel?
"Exercise is about you," Justin advises. "You have to find an exercise or sport or activity that you love.
"A lot of people -- including a lot of my clients -- were active and healthy when they were in school because it's a lot easier to be involved in sports when you're a teenager. But then they went off to college where they started drinking and gaining weight."
This is certainly something I can identify with: during my teenage years I was involved in just about everything from hockey, cross-country and basketball during the winter months to athletics, tennis and cricket during the summer.
However, by Christmas of 2002 -- following my first tentative weeks as a UCD fresher -- endless cycles of training and sports had been replaced instead by sporadic intervals of activity inspired only by an inability to fund the bus from Ranelagh.
But it seems even super-slim models can find themselves in a similar boat. Glenda Gilson, now better known to Irish audiences for her work on TV3's hit 'Xpose' show, also admits: "In school I did hockey, basketball, long jump, high jump, cross country, sprint, swimming... You name it, I did it! While I still love sport and I love to stay active, these days I'm not as active as I should be."
But with a satisfied "life is for living!" she accepts she could never emulate the gruelling VS regimes (incidentally, Roz Lipsett tells me she banished alcohol and sugar and maintained her usual vegetarian diet when preparing for her auditions, while workouts consisted of "lots of yoga and fun classes at the gym") but anyone can see that 32-year-old Glenda has the benefit of rather spectacular genes.
"I've always had great muscle tone, even when I was three years of age," the 5ft 10in beauty tells me. "There's a photo at home of me on the beach away on holidays in 1984 and I have muscly arms and great definition in my legs. It makes me laugh when I see it, but my brother is the exact same.
"When I go to Bodybyrne Fitness [the go-to gym for Dublin-based celebrities], Paul gets a great kick out of my workouts because by the end of a 60-minute session I have a six pack! It goes down after an hour or two but my body reacts so quickly to exercise."
Former Miss Universe Ireland Rozanna Purcell, one of the country's most in-demand models and one who is very much known for her love of working out, hasn't always been so knowledgeable about keeping fit.
Though she too was active as a child -- "I always played on every team growing up, I loved, loved sport" -- she also "fell out of it a bit" when she left school.
It was then that the 23-year-old went through a period of -- by her own admission -- ineffectual exercise.
"My modelling career began in 2009 when I entered Miss Universe Ireland [she would win that competition a year later -- going on to Miss Universe in Las Vegas were she placed an impressive seventh]. Back then I was pretty clueless about what exercises to do or how to work out. I'd just go to the gym -- but I wouldn't go near the weights or machines because I assumed only men did lifting."
She also spent a considerable amount of time running, but knee injuries soon put paid to that.
"I got to a stage where I just couldn't run anymore and was looking for another activity. Then I thought, 'my whole family cycles' so I gave that a proper go. And it turns out I'm pretty good at it!"
Which is something of an understatement: she regularly gets in 80km routes at the weekend, she's already completed the gruelling 160km Sean Kelly race in Dungarvan and, next May, the Co Tippearary native will travel to Austria to complete her first half Ironman: a 2km swim, 90km bike and 21km run.
But such an intense fitness regime clearly has its benefits. Roz's toned physique is admired by both men and women and, as she comments: "At least now with all the training I can have a few more carbs like potatoes and rice -- things that maybe before I wouldn't have felt so comfortable tucking into."
Arguably our biggest name internationally, vegan Rosanna Davison's name alone surely conjures up notions of clean-living. Though obviously always slim and gorgeous, Miss World 2003 seems even more streamlined lately.
"My body has definitely become fitter, stronger and healthier in the 10 years since I won Miss World -- I have training sessions at Bodybyrne Fitness, as well as Pilates classes and regular running, to thank for that," she reveals to me. "In fact, I'm in far better shape than I was at the age of 19!" she adds with a smile, while also acknowledging her "carefully planned, plant-based diet".
Much like Roz Purcell, she recommends weight training for "strong, tight and toned muscles and a great body shape," as well as a diet composed of whole, fresh foods with minimal sugar, processed foods and alcohol -- "they only wreak havoc on the waistline and willpower!"
Justin Gelband reckons that "there's no limit to what you can do physically and how you can perform," hopefully even for lost-causes like me -- the very ones who insist that lifting their seven-and-a-half month baby is exercise enough right now.
But considering his message of "you have to take responsible for your own body", I've slowly tried to reintroduce a much neglected pastime of mine: jogging. And though I may not be quite at a Victoria's Secret level of physical perfection on the completion of my modest 30-minute route, something tells me that at least aspiring to be more Amazonian-like will always be preferable to putting some scrawny size double-zero on a pedestal.