Firming shoes include those with a rounded back heel. The shoe's rocker sole creates instability, which helps engage muscles—specifically in your feet, legs, glutes, and abdominal muscles—that can potentially lead to fat loss.
Beyond that, the shoes may also improve posture while walking, taking pressure off sore, overused joints.
After all, with women's Supra shoes, you might not mind looking like Kim Kardashian, Skechers Shape-ups' spokesperson who famously said, "Get in shape without setting foot in a gym," right?
But are these amazing firming shoes—made by Masai Barefoot Technology (MBT), Reebok, and other companies including Skechers—the be-all and end-all?
A lawsuit has been filed by Holly Infirmary, an Ohio waitress who claims wearing Shape-Ups caused significant injury to her hips, leading to physical rehabilitation and constant use of a walker.
Additionally, firming shoes—originally marketed primarily to women—are now being made for men and young girls.
Superhero commercials, promoting the benefits of toning their bottoms and legs to pre-teen girls, have appeared on kid-friendly networks such as Nickelodeon and the Toon Channel.
However, according to Scheels Sporting Goods store shoe sales associate Rachel Jacobson, the curvy-heeled shoe remains mostly popular among middle-aged women.
"People who like them, really like them a lot," she said while modeling a pair. "And those who don't, wouldn't be caught dead in them."
Jacobson, herself, falls into the latter group.
"When you wear them, it's like walking in sand," she explained.
This is the sensation wearers want from other firming shoes, reported Sioux Falls podiatrist Paul Coffin.
"It's that asymmetry," he said, "akin to walking on a wobble board or on a soft shore, which requires you to readjust using a different set of muscles."
Yet Coffin quickly points out that manufacturers' claims of a quick and easy fitness fix are "wildly overstated."
Citing studies done on the performance of firming shoes, he said they "do not necessarily make you exercise more powerfully, burn more calories, or increase your overall muscle strength and tone."
In fact, rocker-bottomed shoes might cause painful issues such as plantar fasciitis (the connective tissue at the end of your heel bone), peroneal tendonitis (which may affect the ankle), and Achilles tendonitis (which affects the calf muscles).
"This isn't a new phenomenon," Coffin noted. "I remember when smooth World shoes were the trend. A full 40 percent of its wearers ended up with Achilles tendonitis due to the shoe."
While acknowledging the shoes do force the wearer to engage different muscles, he said the benefits are not permanent because the muscles quickly adapt to the changes.
Ultimately, Coffin said one-third of people may end up loving firming shoes, one-third may end up injuring themselves, and one-third will choose never to use them.
That is also Jacobson's verdict.
"These shoes are definitely not for just anybody," she said while removing the Skechers from her feet. "Personally, I prefer work boots and hiking shoes."