Exercise leggings are experiencing a surge in popularity right now, with manufacturers making plenty of scientific sounding claims about their performances — with the price tags to match.
The burgeoning New York sportswear vendor Bandier recently made the New York Post because of its "couture leggings" costing up to $300. Meanwhile, quintessential legging retailer Lululemon's pants start at $98 and even traditional sportswear companies like Nike are now offering leggings for way more than $100.
Bolstered by high-tech-sounding features like compression, thermoregulation, and silver thread, leggings like these might sound worth the money — but is there actually any science behind these claims?
"I know there are several companies claiming a lot, but the scientific evidence mostly is not existent," Billy Sperlich, the author of a study on compression pants' effects on performance, told TI. He added that he couldn't comment on the claims specific companies made unless he was able to run tests. But many of the companies making these claims haven't run tests, either.
Let's take a look at three popular claims and how they shake out compared to scientific studies.
Compression
"Compression" is a buzzword among leggings manufacturers and seems to be the most popular claim when it comes to performance sportswear. This could be because "compression" basically just means "really tight," so it's not that difficult to manufacture. But as it turns out, the benefits are largely backed up by science.
"Anything around compression, people love," Jayne Harkness, the chief merchandiser and chief buyer at Bandier, told TI. "The compression factor is really the retention of the stretch of the fabric. It essentially means it holds you in."
This not only translates to a slimmer appearance when wearing compression pants, but also, according to manufacturers, an improved workout.
You'll also find compression garments being marketed to both the elderly and people flying on airplanes to prevent blood clots. Experts disagree on whether compression works for that purpose, according to WebMD, although some studies have shown that they do.
Companies don't stop at just marketing their leggings as compression pants, though. C3 Fit, which is sold at Bandier, knits fabric with different levels of compression hitting at different parts of the leg and hip. And Vimmia says its compression pants "squeeze" blood vessels, "which allows more blood and oxygen into the compressed muscle and helps shunt waste."
Vimmia couldn't point to any studies proving that compression pants actually affect waste production. But there are plenty of studies that show compression pants can be beneficial.
Studies have shown decreased muscle soreness, decreased swelling and edema, improved blood-flow, muscle oxygenation, and cardiac output, decreased muscle damage, and improved muscle recovery associated with compression garments, according to the site Biological Conclusions. In many cases, though, the difference was small.
"So wearing the garments may not make you run faster or jump higher, but they may help you recover from a tough workout faster and may help decrease the likelihood that you’ll injure your muscles," BC concluded.
In Sperlich's study, researchers found that a compression garment paired with silicone strips that mimic athletic taping helped improve performance during repeated 30-meter sprints. The testers wearing the compression pants were able to increase their step length and they rated their perceived exertion lower than those who didn't wear compression pants.
So it's safe to say that compression pants can make a difference. Whether that difference is worth hundreds of dollars, though, is up to each buyer to decide.
Thermoregulation
The activewear company Vimmia claims to have developed a "smart yarn" that uses "bioactive minerals" to "absorb the far infrared radiation emitted from an individual's body heat and re-emit the energy back into the body, which leads to increased blood microcirculation in the skin tissue and aids in thermoregulation."
This means the smart yarn should help keep you cooler in warm temperatures and warmer in cool temperatures while helping you maintain a constant core temperature, the makers say. Plus, according to Vimmia Vice President Alex Raminfar, this increased circulation can improve the appearance of the skin.
The company claims these pants can reduce the appearance of cellulite if they're worn for six hours a day 30 days in a row. They start at $125.
Independent researchers haven't studied this particular "smart yarn" fabric, but there are plenty of studies that test whether thermoregulation can be affected by clothing during exercise — and the results are far from unanimous.
An April study from Hong Kong Polytechnic University measured the temperature of women who were working out with sports bras that had "dynamic moisture transfer properties" compared to women wearing typical sports bras and found that the high-tech sports bras actually helped keep the women's bodies cooler.
But a similar study published in August found the opposite: a cooling fabric had no effect on thermoregulation. And yet another study found that your best bet for improving thermoregulation during exercise would be to work out semi-nude. And a much-referenced study from 2001 also found taht clothing fabric doesn't affect thermoregulation during exercise in moderate heat.
With all these conflicting reports, it's tough to tell whether a specific product is the real deal or not. According to Dennis Jensen, the graduate program director of the department of kinesiology and physical education at McGill University, claims like the ones made by Vimmia are "simply speculation and conjecture" if they don't come with studies to back up the claims.
So basically, if you want to buy leggings that actually affect thermoregulation, do your homework. It all depends on the product and how much science is behind it.
Anti-microbial fabric
Bandier, the upscale fitness boutique in New York City, sells a line of products with a pretty outlandish-sounding claim. The brand, HPE, has a patented fabric called Freshfit that actually has a silver thread embedded, which Harkness told me renders the fabric "completely antimicrobial."
"No joke, this works," she said.
As it turns out, there's actual evidence to back this up.
A Wall Street Journal story from 2006 examines the use of silver particles to reduce microbes through soaps, dishwashing machines, and other products. Silver has been found to kill microorganisms ranging from e. coli to staphylococcus bacteria, WSJ reports.
In fabric, the use of silver to discourage microbe growth isn't even new. It has been employed by both the U.S. and British military, as well as outdoor brands and hospital bedding, WSJ reports.
HPE also notes on its website that it has conducted independent tests on Freshfit, and they found "no growth" in certain bacteria when compared to fabric that didn't include silver.
The important thing to remember with all of these features, as Jensen said, is that without being backed up by trials, any claims made by the manufacturers should be taken with a grain of salt.
"If the methods are appropriate and the study is well designed and adequately powered to show a meaningful difference and, in fact, a meaningful difference was observed, then the claim has merit," he said. "Otherwise, I suppose you could say it’s marketing mumbo jumbo."
But, as Christine Mosher, director of retail operations for CorePower Yoga and Pure Barre, points out, sometimes the placebo effect is all that matters.
She maintains it's worth it for customers to spring for high-end leggings. Leggings that are designed for exercise will make it easier to focus on your workout, she said, and can make you feel more comfortable.
With leggings like these, exercise enthusiasts "will feel better about themselves," she said, "which may turn them into avid exercise enthusiasts."
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