Fact: A Pair of Leggings Can Track Your Muscles While You Work Out

leggings smart tech enabled 51 Fact: A Pair of Leggings Can Track Your Muscles While You Work Out


It was recently brought to my attention by a celebrity personal trainer that after more than a decade of gym-going, I wasn’t squatting correctly, and my sloppy form wasn’t doing my body any favors. Specifically, the way I—and apparently many other people–rush through a set of squats often means technique is compromised, and instead of my butt doing the heavy lifting, the quads and the front of the thighs compensate. The PT told me this leads to “chunky thighs” that would only get worse the more I worked out. Yay.

On a mission to perfect my form, without the cost of weekly sessions with a celeb-vetted PT, I discovered Athos, a clever fitness startup creating tech-enabled activewear. I’ve tried basically every wellness gimmick out there, but this one truly excited me. Here’s why: By syncing up with an app on your smartphone, the clothing can tell you whether you’re exercising correctly and how hard. Bingo!

“The leggings can track muscle effort in real time and also [your] heart rate,” cofounder Dhananja Jayalath told me. “By seeing what your muscles are doing, you can better understand if you’re working the correct muscles to the right extent and if you’re balanced left to right.”


Athos has tech-enabled activewear for men and women.

Right now, the brand has pieces for men and women, with the activewear starting at $149 for capri leggings, and the tracking device (which you attach and detach from garments and use interchangeably across the entire line) is $199. I ordered the capris and device and then downloaded the free app.

The first thing I noticed about the Athos leggings when they arrived was that they look basically exactly like regular workout pants, except for a ton of sensors on the inside. There’s also a small pocket on the side of the leg, which is where you clip in the tracking device—a piece of technology that uses Bluetooth with your smartphone, where data gathered from the sensors is stored.

“The sensors read surface EMG (electromyography), a technology that has been used in sports performance institutes for years to help athletes improve form. With EMG, we can understand how your muscles are working in real time to give you the visibility to things that you can’t feel or see in the mirror,” Jayalath explained. 

After I paired my Athos device and phone, the app prompted me through some assessment exercises to test the sensors. All good. Next, I jumped straight into my workout, focusing on basic lower-body exercises such as squats and lunges to evaluate the technology and ace the technique. Muscles being used heavily burned bright orange or red, and secondary areas lit up blue or light yellow. You can see my (slightly imperfect) squat here, which I was able to fix within 10 minutes of tracking my muscles and adjusting my technique. It really made the whole thing simple—way simpler than trying to follow a personal trainer’s instructions while watching yourself in the mirror.

athos activewear

The app showed me in real time what muscles were working.

After you’re done, a report pops up, explaining exactly how hard you worked each area of the sensor-covered areas of your body. As someone who has tried dozens of gimmicky fitness-tech innovations, I have to say this one’s damn impressive, and useful—particularly if you’re new to exercise and don’t want to pay for weeks of personal training, or if you’re a regular who wants to get the most out of every session.

athos activewear

I was shown a full breakdown of my workout.