These smart glasses became my erratic personal trainer

Fitness wearables don't have to go on your wrist -- although it makes sense that most of them are designed that way. We've been wearing wristwatches for generations, so it's a place where we're used to tethering something. But how about the original wearable: eyewear? JINS Meme is a pair of unassuming smartglasses that have highly sensitive three-axis gyroscopes and accelerometers inside. And because they're situated on your head, the Japanese eyewear company says it can offer insight into your posture and balance and pinpoint weaknesses. To help you with all of the above, JINS recently launched a core-training application ("taikan") to complement its existing running-coach app. It tests your core strength (think: abs, back, abductors, butt, etc.) and offers a live critique on how you're doing. Here's how training went.

As I've written before, JINS' smartglasses are unassuming and normal-looking. In Japan, there are several frame styles to chose from (including the aforementioned running version). The only sign that there's something different here can be found in the arms, where the battery, gyros and Bluetooth radios add some bulk. I'm a regular four-eyes, so wearing them poses no extra burden for me. I've already shared my feelings on running, so instead of that app, I focused on the gym- and yoga-mat-friendly core-training companion. Despite using the day-to-day frames, which are less sporty than the sunglasses, they're well-fitting enough that I was able to lunge and plank without concern.

And now for the main piece: the training app designed to improve your posture and those all-important muscles surrounding your torso. No, these exercises don't aim to give you a six-pack (the training is gentle, sometimes challenging, and you're only competing against yourself), but what you get from the app is useful, applicable feedback.

Your workout is orchestrated by a JINS-glasses-wearing personal trainer (a cross between the Wii Fit Trainer and Janine from Ghostbusters) who offers detailed instructions (in Japanese), giving you reminders on what to focus on as you practice the movements. For example, when lunging, you want to maintain a vertical body line. You know this, but you may have a tendency to sag midway through the test. The digital trainer will ensure you're at least trying to do things right.

For anyone who's active (especially people into yoga or other activities that help with balance and core strength), you may find it all a bit too easy -- but then this probably isn't for you. It's better pitched at rookies and anyone wanting to improve their posture or focus on their weak spots. The app is free (the glasses are not), but it doesn't house an extensive range of exercises. Once you're getting scores of high 90 across the board, it appears that you've reached the limit of what the app can help you with. (But good for you!) It's precise too: When I wobbled on a squat or let my head drop on an otherwise simple exercise, my score dropped. It even composes line graphs after each workout, showing any imbalances to the left or right.

My terrible posture is a chronic habit, and having a robotic personal trainer tell me that I'm screwing up is a pretty good way to keep myself in check.

The app keeps a record of your score even if you don't want it to, so you can see your numbers improve. However, the setup isn't perfect. Those planks I mentioned? I have a constant score of zero. I don't even know how it's possible to be that bad at a side plank. (I attempted this exercise six times. I got the same score.)

What's more, the primary app that you need in order to use the glasses often wouldn't register that I was wearing them, and its eye-monitoring sensors deduced that I had the mind of 42-year-old (based on the fatigue detected in my eyes) with the body of a 63-year-old. That's both cruel and highly specific. When it comes to your body, JINS Meme offers a score for your energy levels, posture and stability, while your mind is scored in terms of concentration, energy and composure. Sensors inside the bridge of the glasses detect minute changes in electromagnetic activity from your eyes, calculating where your eyes are looking and how often you blink. It sounds crazy, but it's real. While the glasses can monitor tiredness in real time, there's no kind of useful feedback for this feature just yet.

To demonstrate my aging state, the app displayed a wavering, drunken head. While my posture isn't perfect (thus the core training), I'm no bobblehead. JINS told me that the glasses adjust to the wearer over time, getting more precise and calibrating to the user. Or maybe I am in such a bad state?

The current apps and glasses are just the start: The company has hinted at moving beyond Japanese borders (it already has a "normal" glasses store in San Francisco), so these smart glasses, or some variation thereof, might have a chance of hitting retail in the West.

As a fitness wearable, the JINS Meme is surprisingly effective, but the shallowness and erratic nature of the app limited how far I could go with it. Surprisingly, there was nothing uncomfortable about wearing a fitness tracker on my face -- but then, I'm a glasses wearer. If you aren't, you might feel a little weird wearing something while you work out.