Ever since Sony made music portable with the Walkman, people have been listening to music during their workouts. With the iPhone’s ability to function as an iPod, all you need is an appropriate case and you can stop carrying around an iPod for gym sessions. Uniea’s U-Motion case is one such case, and after several weeks of use it’s time to evaluate how well it does the job.

The U-Motion holds the iPhone securely on your arm.

The idea of armband-style cases is pretty simple. Strap the music player to your upper arm tightly enough so that it won’t slide around, in a position that allows easy access to the controls. The U-Motion certainly fits that bill, with its translucent plastic cover allowing the iPhone’s touchscreen to work normally.

The devil, however, is in the details, and that’s where the U-Motion starts diverging from the ideal.

The metal D-ring that connects the two halves of the armband is rather uncomfortable when running, because unless you strap the case to your arm like a tourniquet, the motion of running causes the case to slide down your arm to the crook of your elbow, where the metal rubs your skin. Workouts involving less arm motion or a long-sleeve shirt under the U-Motion aren’t as prone to this problem. For runners, though, the issue might be alleviated by using a smoother finish on the D-ring, or by making it of a different material or shape. Kudos to Uniea for making it of what appears to be chrome-plated aluminum, so it won’t rust, although stainless steel would have been significantly stronger.

That metal clip tends to irritate my arm when running.

More worrying than the discomfort of the D-ring is the design of the pocket for your iPhone. The opening for the phone is in the back of the case. That means, the opening is against your arm when you’re working out—and that means, your iPhone is going to get sweaty.

For some inexplicable reason, Uniea put the slot in the back of the case, exposing the iPhone to sweat.

I do most of my indoor workouts in the winter in hotel fitness centers, so I almost always have a plastic room key that I need to keep with me. I get around the sweaty-iPhone problem by sticking my room key in the case behind the phone, which means that the sweat gets on my room key instead. I can live with that, but a much better solution would have been to put the opening in the top of the case or even in the front, so that there’s no risk of moisture getting to the iPhone.

This seems like a glaring oversight on Uniea’s part, especially since they had enough forethought to make the metal D-ring out of a reasonably sweat-proof material.

You can see the distinct rectangles of hook-and-loop fabric here. The band would have been much more easily adjustable if it were made of continuous hook-and-loop; as it is, the band tends to settle in the thin areas between the rectangles.

The armband’s construction is somewhat of a mystery, too. Rather than explaining it all in words, I’ll just refer to the photo, where you can see what I mean. Making the armband out of one solid piece of hook-and-loop fabric would allow for easier adjustability, as the D-ring tends to fall naturally between the rectangles when adjusting the band. The tiny amount of elasticity given up by such a design wouldn’t be missed, and once the armband is adjusted, your arms aren’t going to get significantly larger or smaller over the course of one workout anyway.

The plastic window in the case isn’t clear; it’s translucent, and noticeably so. This isn’t a huge problem since you probably aren’t trying to read while staring at your arm during a workout, but the iPhone’s screen is noticeably blurry and slightly dimmer through the plastic. Clear vinyl is certainly available, so it’s a bit of a mystery why Uniea didn’t use it here.

The plastic cover over the phone isn’t totally clear, causing text to be noticeably blurry.

Finally, Uniea makes a big deal of the cable management. Because I use a couple of different music players on a regular basis, and because the U-Motion isn’t the only iPhone case I use, storing earbuds on the U-Motion’s armband doesn’t make a lot of sense to me. If you don’t ever use headphones except at the gym, though, you’d probably find this feature more useful. However, the cable management is only useful when storing earbuds; it’s totally useless when you’re actually working out and wearing the case.

Despite the blurriness, it’s still reasonably easy to see and control the iPhone through the case.

If you’re the type who can’t work out without music and you spend a lot of time in the gym, a case like the U-Motion is well worth the $25 to extend the utility of your iPhone. After all, an iPod shuffle is still more than double that price, and a Nano is at least six times as much, and neither one comes with a case of its own. However, I’m not convinced the substantial disadvantages of the design make the U-Motion the case for working out with your iPhone.

Copyright © 2010 Chris Lawson. Reviewing in ATPM is open to anyone. If you’re interested, write to us at reviews@atpm.com.