Do ankle weights really need to be smart? We tested some to find out.

By now, there’s a smart version of just about every type of workout equipment: treadmills, stationary bikes, kettlebells, boxing gloves, goggles, and even entire home gym setups. Whether you want to monitor heart rate, track calories burned, follow individualized workouts, receive form cues, or compete with other exercisers, there’s probably a product out there that’s compatible with your activity of choice.

Now, ankle weights are expected to finally enter the smart equipment playing field. In fall 2021, Chinese company Sportneer — which sits at the intersection of sports and engineering — launched a Kickstarter campaign for “The World’s First Smart Ankle Weights.” The TrainNTrack ankle weights were supposed to start shipping January 2022, but their Kickstarter funding was unsuccessful, so it’s unclear what’s next for them.

With a sensor that tracks motion and heart rate, these weights look similar to, but go beyond, the traditional wrap-around style of ankle weights, theoretically promoting smarter, more intentional training. Before they’re released to the masses, I had the opportunity to try out the Sportneer TrainNTrack weights for nearly two weeks myself, to determine if they’re worthy of a smart upgrade. Here’s where my trial led me, and what potential buyers should consider before purchasing:

The setup is fairly simple, with a few kinks

Getting a pair of TrainNTrack ankle weights up and running is a pretty simple process, assuming you have the user manual handy and are willing to spend a few minutes following it.

Since the weights arrive uncharged, the first step is to charge them up using a magnetic charging cable. (I’ll spare you the confusion that I faced at this point by letting you know that, although my set included two weights and two charging cables, only one of the weights is “smart” and can be charged. The manual did not make that very clear.)

Once charged, you then download the Sportneer app, create a login, and pair your weights to your phone by pressing the button next to the charging port. After you’re connected, you can then strap on the weights using the buckles and Velcro, choose an exercise program, and get to work.

The battery life is excellent

A battery life of 35 hours is impressive, no matter what device we’re talking about. Although I didn’t use them for enough hours to verify Sportneer’s claim, I can vouch for the battery’s generous capacity. I charged it up for a few hours right when it arrived, and did not see the indicator light change from green (which signals a full charge) over the course of several training sessions. Theoretically, even if you used the weights for an hour every single day, you’d have to recharge less than once a month. If only phones and GPS watches could hold that kind of juice!

The weights are constructed with quality materials

Just holding the smart weights, they feel softer, smoother, and more durable than traditional ankle weights. While I’m used to ones with a scratchy exterior and rigid shape, the TrainNTrack weights feature soft iron stuffing on the inside and a composite Lycra fabric on the outside.

They aren’t designed for petite people

Unfortunately, I quickly ran into the same problem with the TrainNTrack smart weights that I have with many of the smart watches I’ve tested: the size. I’m 5 feet tall with petite ankles and wrists, and these weights clearly were designed with larger people in mind.

When wearing them on my ankles, I either had to strap them so tightly that it was constricting, or settle for a more comfortable but less secure fit. (More often than not, the weights slid up and down my ankle either way.) And forget about a snug fit on my wrists, if I hoped to use them there too. The weights were simply too big and inflexible for my small arms, and I never did figure out how to keep them in position.

The smart weights don’t fit properly on small wrists.
Credit: Sportneer

Not only does the large size distract from the workout — especially with quick and expansive movements like jogging, butt kicks, and jumping — but the poor fit also makes the heart rate reading less reliable. In sum, because of my size, I did not feel like I could maximize the benefits of the Sportneer smart weights as much as a larger person might.

The performance-tracking technology is impressive

Before I tried out the TrainNTrack smart weights, I was skeptical of the “smart” component. Then again, I hadn’t yet heard of a six-axis gyroscope. A little research informed me that the technology driving this product is a sensor with three axes that measure turn rate and three axes that measure acceleration. These sensors, I learned, are also used in aircrafts, digital cameras, driverless vehicles, and navigation systems. So might they be a bit overkill for ankle weights? Sure. But at least they seem to be legitimate.

The free app includes training tutorials and a ton of data to geek out on

I appreciate that the Sportneer app is free for all customers and comes with a wide range of training courses and exercises from aerobics and arm shaping to squat training and indoor runs. Once you decide what you want to do, you simply press “start exercising” and follow along as a personal trainer demonstrates the workout. While the trainer does a good job showing what the exercise is supposed to look like, I’ve never been one for digital workouts, and this one was no different. (I’ll always prefer learning something in person and then going for it on my own over staring at a screen and trying to replicate what I see.)

It didn’t take me many workouts to arrive at the conclusion that the idea behind the Sportneer TrainNTrack ankle weights is intriguing, but ultimately overkill.

The screen also shows a timer, your heart rate, and your training score. Being a natural skeptic of arbitrary metrics such as “workout readiness” and “5K prediction,” I wasn’t sold by the training score. All I know about it is that “the higher the accuracy, the higher the score.” But I do appreciate the detailed summary that follows each workout and offers feedback on training duration, calories burned (which should always be taken with a grain of salt), and exercise precision. Accuracy aside, for many people, keeping track of their workouts and comparing one to the next can be a great way to stay consistent and motivated.

The experience is somewhat customizable

There are four different sizes of TrainNTrack smart weights to choose from: 2 pounds, 3 pounds, 4 pounds, and 5 pounds (each of which denotes the weight of a single unit). I was sent a 3-pound set to try—which was fortunate, given that the 2- and 3-pound sets are for ankles that measure a minimum of 9.4 inches around, while the 4- and 5-pound are for 11.4 inches or more. The maximum size for the lighter two sets are 17.3 inches, and around 19 inches for the heavier two.

Unfortunately, the weights cannot be interchanged, meaning that whichever size you choose, you’re stuck with (unless you decide to upgrade). In a perfect world, you’d be able to slip weights in and out so you could gradually increase the load alongside your rising fitness.

Adding to the customizable experience, TrainNTrack weights can also be used in a traditional (not smart) manner. If you crave a workout without the feedback offered by the app, removing and replacing the module from its slot is easy and quick, as illustrated by the user manual. However, if you think you may be doing that frequently, you should probably consider whether these high-tech weights are worth the investment.

Purchase or pass?

It didn’t take me many workouts to arrive at the conclusion that the idea behind the Sportneer TrainNTrack ankle weights is intriguing, but ultimately overkill. While nothing about it is overly complicated, I found the whole process to be more tedious than necessary and would rather have just strapped on some old-school ankle weights and gone to work without fussing around with the app, the poorly-fitting weights, or the rather arbitrary metrics.

Maybe I’d have a different opinion if I were a more regular user of ankle or wrist weights, or if I needed help in the consistency department. But because weights like these will never comprise the bulk of my training, it’s hard to imagine dropping a chunk of cash on more equipment that will largely go unused.