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Under Armour Armour39 review: This serious fitness tool could do more

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MSRP: $149.99

The Good Under Armour's Armour39 is well-suited for hard-core athletes who want an accurate measurement of their most vital workout stats. The tracker uses a clean and easy-to-read iOS app, which syncs via convenient wireless Bluetooth connection.

The Bad The Armour39 is too cumbersome to wear all day, and you must strap it on before you work out. Using it without an iOS device provides much less information. There's still no Android version of the app, and the Armour39 doesn't record steps.

The Bottom Line The Armour39 is meant only for hard-core fitness fanatics, but even those gym rats will be left wanting more.

5.0 Overall
  • Design 5
  • Features 5
  • Performance 5

Review Sections

With the $149.99 Armour39 system, Under Armour branches out from its comfort zone as a sports apparel manufacturer to make its first foray into the burgeoning fitness-tracking craze. Unlike competing fitness products, such as the Nike FuelBand and Fitbit Flex, which almost anyone can use, the Armour39 is meant for serious athletes seeking to boost their training regimen.

Indeed, with a sizable strap that goes around the torso, it's much more than just a tiny device you wear on your wrist. But once they hit the gym, even its target audience of extreme fitness fanatics may find the Armour39's intensity lacking. It keeps tabs on your most vital fitness data, then electronically transmits those stats to an iOS app, but missing features keep it from delivering a complete experience.

When I first held the Armour39 fitness-monitoring strap, I was a little concerned about wearing a gadget that needs to make skin-to-skin contact with my chest. I also didn't want something under my shirt possibly irritating me as I exercised. To my surprise, though, the strap fit snugly around my torso and easily stayed fastened with simple hooks. At times, I barely noticed it was on, but it's not something that you'll want to wear for hours on end.

With yellow accents and a gaudy paint job, the Armour39's design isn't for the timid. Sarah Tew/CNET

Yellow curvy lines flank the front of the black stretchable strap bracket, which acts as a center circular dock for the removable yellow "bug" and is boldly emblazoned with the Under Armour logo. The bug itself is about the size of a 50-cent piece and sports an indicator light that routinely blinks red, letting me know that its Bluetooth connection is working. I do find the splashes of yellow as well as the large Armour39 logo on the side of the gadget a bit garish. Still, it's really a moot point since the device is meant to be worn under your clothes.

The tracker uses a watch battery that's replaceable, but not rechargeable. Sarah Tew/CNET

Rather than a rechargeable battery, Under Armour opted to put in a regular watch battery in the bug. One benefit is that you never have to worry about recharging the device. But you will eventually have to replace the battery. The company told me that the battery is expected to last more than a year if you work out an hour three to four times a week.

That you have to actually put on the Armour39 prior to working out sets it apart from other more casual fitness trackers, which are typically worn throughout the day and track overall activity more than a specific workout. That probably won't be an issue for the devoted workout set, but I don't want to have to remember one more thing to bring to the gym. I mean, it's hard enough to get me there in the first place.

The core metrics of Armour39 are heart rate, intensity, and calories burned. But like what Nike has done with the FuelBand and NikeFuel points, Under Armour has echoed via something called WillPower, its own proprietary measurement of how hard you worked.

The companion app is easy to use and displays information clearly. Roger Cheng/CNET

Also akin to NikeFuel, WillPower is only effective if you buy into it. WillPower takes into account how long you worked out, your gender, height, weight, and heart rate, giving you a score between 1 and 10. Personally, I only got as high as the 5.5 mark, so I probably wasn't pushing myself very hard, but I'd like a more meaningful metric.

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