I tried a mini computer to count my CrossFit reps while I worked out

CrossFitters have embraced many fashion trends that the non-initiated may balk at, because fashion has to meet function during a WOD. First there were compression knee socks, then there were booty shorts covered in pastry prints, and now we’re living in a world where the Nexus, a high-tech arm sleeve, counts reps for you.

Nexus is geared to adding a little #science to CrossFit. Inside this sleeve sits a what I’ll call a “mini computer”, which is the shape of a snack-sized Kit Kat, and it provides information about your reps. “Other trackers do not tell the story of the exertion you are putting your body through externally. Nexus can measure your physical movement patterns, counting reps, and providing meaningful information about your performance and fitness,” explains Mike Dawson, the brand’s CEO.

Before the workout, you let the Nexus app—which you sync up to the device using Bluetooth—know which workout you’re planning to do for the day. You can execute pre-programmed workouts, go for “AMRAP” (as many reps as possible), or power through for time. It sounds complicated, but it takes me roughly two minutes to execute, and I usually do so during my pre-WOD nervous pee.

During your workout, the device literally counts and tracks your reps for you. Then after, you can check your round-by-round splits, cadence, work-to-rest ratio, and the Nexus-invented power metric that calculates your overall intensity into a raw metric on the app. “This gives you info that can help you pace better in the future, find weaknesses, and gauge transition times,” explains Dawson, assuring me that the Nexus had been programmed to recognize all the movement-staples in CrossFit: double-unders, box-jumps, handstand push-ups, toe-to-bar, kettlebell swings, muscle-ups, etc. But TBH, I didn’t believe him until I tried it myself. Here’s what happened.

What happened when I tried Nexus rep counter

For my first workout, I decided to stick to the basic movements and did “Cindy” (5 pull-ups, 10 push-ups, and 15 squats over and over for 20 minutes straight without a break). For my second workout, I did something with more complex moves: ring muscle-ups, double unders, handstand push-ups, box jumps, and toe-to-bar. It’s not that I was trying to trick the device, per se, but I wanted to see if it could it keep up with my high-skill demands.

My first impression was: Wow, a sleeve is so much better than a watch for CrossFit. I’ve tried watch-style wearables in the past, and the wrist is really not an ideal location for a lot of CrossFit moves. Maybe the fact that the wearable didn’t get jostled or bumped during my workout is to thank for its accuracy, but truthfully, I was astounded by how good the device was at counting and tracking my reps and keeping up with my varying movement patterns.

As for the data available post-workout? In a word, it was thorough. I actually found the amount of data available to be a little overwhelming. I’ve always known that my transitions between movements need work, but the data backed that up. There were, however, a few nuggets of info that surprised me. For example, I’ve always known my handstand pushups were “meh”, but I had no idea I was taking close to three or four seconds per rep. And though double-unders are always tough for me, I was shocked that it took me almost three times as long in the last round.

While Dawson told me that the device can be used by anyone from beginner to Games athletes, after two weeks of using the Nexus and poring through the data, I suspect it’s really the professional athletes who will get the most out of this gadget.

I have a goal of breaking into the top 100 female athletes in my region—and maybe I’ll know better how to use this device when I inch further from “recreational CrossFitter with goals” and closer to “Games athletes”. But for now, I know what my weaknesses are (snatches are hard! My hamstrings are weak! I should probably be able to touch my toes!) without the fancy data.

Will I ultimately continue using this smart-sleeve? I’m not sure. On one hand, I’m not totally clear on what actionable next-steps I can takeaway from the data. But on the other, I like the way the sleeve makes my arms look (#strongissexy) and analyzing the data is fun.  As it turns out, I may not need some smart-tech to track my reps, but that doesn’t mean my number-geek fashionista self doesn’t kinda love it anyways.

If you’re looking for more fitness apps to add to your phone, check out Obé or Whoop. And if you’re thinking about giving CrossFit a whirl, read this.