There's no shortage of devices that track workouts, but a new crop of gadgets that help you make your workouts better is slowly growing. One of the newest is the $99 Lumo Run, which is a scaled-down version of the company's smart clothing. It's a super-small sensor that monitors running, analyzes form in real-time, and provides feedback on how to run better.

In some ways, that might seem limiting: unlike so many activity tracking wearables that are great for people looking to exercise more, Lumo Run doesn't track daily steps, sleep, or nutrition. Devices like Lumo Run are meant to be used during workouts by people who already have an exercise routine and are looking to improve it. The device might not have as wide an audience as a more basic fitness tracker, but once you're in a routine, the Lumo Run may actually be more helpful.

Design: Free thy wrists!

I'm always interested in fitness wearables that don't strap around my wrist, and the Lumo Run fits that bill. A bit of history: the company's first product was the Lumo Lift, which helps correct posture. Lumo moved on to smart clothes, including $169 pants with a sensor in the waistband that monitors running. Since smart clothing is more expensive than a just a sensor, the company recently began selling the sensor by itself for $99, along with a clip to attach it the waistband of your choice.

Before we talk about how it feels to wear the Lumo Run, let's look at the sensor itself. It's a thumb-sized, black oval with a silver logo in the middle of one side. At the tip of one end of the sensor is a partially removable cap that hides its microUSB charging port. The cap is a little annoying to unfasten—I felt like I was going to break a nail every time I tried—but thankfully the Lumo Run is supposed to last a month before it needs recharging. If you run regularly, or at least once a day, battery life will be shortened. After five days of use, my device's battery was half gone.

The sensor's clip is the same shape as the sensor. Sliding the sensor into the opening on the clip is harder than it looks, since the opening is just about the same size, giving you very little wiggle room to push it in. Once the sensor's secure though, it's unlikely to pop out. The plastic clip portion is also really tight, so when you slide it onto the top of your waistband, it feels sturdy—you'd have to take a hard fall or jerk your body around for it to come off.

The Lumo Run didn't budge during my runs. The portion of the clip that touches skin can be prickly at first, but it wasn't enough to make me uncomfortable or to make me stop running. I also never felt like I had to check if the device was still there—there were plenty of times that I finished running and didn't realize the Lumo Run was still attached until I sat down and felt it against my lower back. Thankfully, even if you didn't take off the device before washing your workout clothes, the Lumo Run is machine-washable and waterproof up to 10 meters.

Valentina Palladino

Valentina Palladino

Valentina Palladino

Features: Run until you drop

Much like the Moov Now, the Lumo Run helps you improve your running form. The first time using the device, you can just run, or you can take a ten-minute running test that assesses your form and gives you tips on how to improve. I chose to do the running test, and now that I've recorded a bunch of runs, I can say that it's almost identical to when you "just run." The app counts you down from five seconds to start the run, then a female voice in your headphones explains what the device is assessing. She chimes in every once in a while after that to let you know the kinds of things she'll tell you while you run—cadence, pace, and more—but mostly you just run for ten minutes and then stop to get your results. Throughout the test, you can listen to music from whatever source you want on your smartphone, be it Pandora, Spotify, or something else. The music's volume is lowered when the voice wants to tell you something.

At the end of my test run, the app said I should work on my cadence, specifically getting in more steps per minute. This advice made sense since I tend to run with a high bounce, taking long strides with a good amount of force that results in a spring to my step and fewer steps per minute. The app gave me a goal of 158 steps per minute, and that wasn't as easy to achieve as it sounded. During my next recorded run, sound effects pumped into my ears—a high, congratulatory tone when my cadence was on-point and a low, sad trombone-like noise when it was lagging. By the end of that run, I never wanted to hear that low tone again. Because I wasn't used to running with such quick cadence, I heard the trombone nearly every two minutes. I also heard it incessantly because I chose the "immediate feedback" option in the app—if the sensor knows you're not running properly to reach your goal, it will let you know with that sad tone immediately, and do so every time you fall off the wagon.

Even though the sad sound effects made that run annoying, the feedback worked. Each time I ran after that, I found myself moving my feet more quickly to get more steps in per minute. When I recorded a run again with the Lumo Run, I heard very few sad trombones and many more happy chimes. It felt good. I'm not sure if my improvement was because I subconsciously didn't want to hear those negative tones, or I just got accustomed to running with higher cadence, but the method worked. Even after I stopped using Lumo Run, I still run with better cadence than I did before... most of the time.

Unlike the $79 Moov Now, Lumo Run only tracks running. Moov Now can track other activities including cycling, swimming, and strength training, and has a number of preset workouts you can follow. Lumo Run just has you running to achieve certain goals. This limits its flexibility, especially if you regularly do other workouts besides running. However, dedicated runners, or those looking to perfect their form, will appreciate the Lumo Run's focus.

If you use Lumo Run on a treadmill, its in-app measurements for distance and pace won't be very accurate. That's because the Lumo Run automatically connects to your smartphone's GPS, so the map generated in the app will look like the scribbles of an angry fourth grader. A Lumo Run representative told me that the GPS won't get an accurate measurement of distance or pace when you're on the treadmill, so you'll have to make do with the measurements the treadmill gives you. Pace and all other metrics should still be accurate, and I found those didn't vary much between different treadmill workouts.

Listing image by Valentina Palladino