Most humans would have trouble walking in these boots, let alone scaling a Jacob's Ladder cardio machine and "running amok" with a notoriously-tough celebrity trainer like Gunnar Peterson (BTW, he's one of the trainers responsible for Khloe Kardashian's "revenge body", among other fabulous clientele). It's your choice whether you care more about fashion than you do function, but the gym is one place where perhaps you should care a little more about what you're putting on your feet — especially if your footwear of choice keeps your calf in a compressed position. "Wearing heels in the gym creates muscular imbalances," says Jill Miller, creator of the corrective exercise format Yoga Tune Up and author of The Roll Model Method. "If her calf muscles are restrained by the position of the shoe, she can't get the full range of motion that would allow her to work her legs and body." Because she's a fitness expert, Miller also can't ignore that the position of Mariah's foot on the ladder above isn't giving her the momentum she needs to climb it. "You get your best boost from your calves and butt when you're climbing uphill or on a ladder, and she can't get the most strengthened outcome if she's on her tip toes," Miller adds.
It turns out the white high-heeled booties are from Rihanna's Fenty Puma line, and Riri re-reposted the Instagram with the tagline, "Yo I made it!!!" These $600 stilettos have a four-inch heel and very tapered toe, according to the product information, and are probably not intended for vigorous exercise. Wearing heels anywhere changes the mechanics of the joints in your foot, and throws off every muscle from the bottom of your foot up. And for each millimeter that your heel is lifted above the ball of your foot, every single muscle and joint is going to compensate that much more, Miller says. "Typically high heels also have a tapered toe, and that narrows the distance between your toes and crams all the bones into a narrow space," Miller says. "It's like if you wrapped your hands in duct tape and say, 'Okay, type!'"
Outside of Mariah's world, there's another universe where it's acceptable to exercise in stilettos: heels dance. Professional backup dancers have developed this type of dance for the mainstream audience, and classes focus on teaching movements that are safe and even practical to do in a pair of high heels. The difference between heels dance and what Mariah is doing is that one involves an instructor who (hopefully) shows you how to move without hurting yourself. But Miller says the aesthetic is not worth the stress you're putting on your body. Most people are unaware that there's muscular tension in their legs (and entire body) from heels, because if you wear them often enough your body adapts to wearing them, Miller says. "For a performer like Mariah, she depends on being able to strut on stage, and in heels, she's not allowing her legs to have a full range of motion," Miller says. Wearing heels might just be part of who Mariah is, in which case, fine. But then again... I don't know her.