I have poor posture — a habit that began long before I sat behind a computer for eight hours each day. I usually blame it on my tallness, but research suggests poor posture and the back pain it causes is much more widespread.

Back pain is a leading reason for doctor's visits, just behind the common cold. Studies find that standing tall contributes to confidence and attractiveness, as social psychologist Amy Cuddy reveals in her TED Talk.

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So when I heard about a new wearable gadget called LUMOback that vibrates when you slouch, I only wished it had arrived a bit earlier — perhaps puberty, when "stand up straight" was so common a refrain in my house that we shortened it to the code word "watermelon." Now, of course, old habits die hard.

Image: LUMOback

The device looks like a belt, is unnoticeable underneath clothing and costs $150. The iOS app it pairs with is compatible with the iPhone 4S, iPad 3, iPod Touch (fifth generation), iPad Mini and newer devices. LUMOback's battery itself lasts three to five days, and it can be charged via USB.

But as an adult, do I really need a fancy device to help me sit and stand correctly? In recent years, the single activity that improves my posture the most is taking a boxing class, likely because it focuses on core strength. But the fact that it requires taking an extra hour out of my day gave me pause — sometimes I don't have that time to spare. Plus, I'm told that hitting the gym for an hour won't counter the eight hours spent sitting at the office with poor posture.

When I met Monisha Perkash, founder of LUMOback, I asked if I could borrow the device to see if it made a difference in the way I sit, stand and move.

The following is a log of my first three days, which I spent (mostly) committed to my new posture-obsessed gadget friend.

Day One

After I unboxed LUMOback, I charged it via USB at my computer. I quickly realized the LUMO app was not compatible with my iPhone 4, so I needed to borrow an iPad to use it.

Once I downloaded the app, it automatically linked with the device in range. I created an account, and the app had me perform a few tasks, such as walking and sitting, to calibrate.

I'll admit that I was initially scared of the device's vibrating. The day before I started wearing LUMOback, I preemptively tried to fix my posture on my own, as if that would lessen the penance I owed from years of slouching.

The good news is that you can set the intensity of the vibrating, depending on how strict you'd like LUMO to be.

Image: Mashable

On the first day, the best part of using LUMO was showing off the app. It features a happy green stick figure who mimics you as you walk, sit, lie down, etc. When you slump, he becomes a sad orange stick figure, and possibly red, if you're really bad.

But this feature of LUMO, I believe, is not just for fun. I kept the borrowed iPad on my desk, facing me, for the entire first day. Why? Because when the gadget vibrated, I honestly didn't know how to move in order to fix my posture. I'm sure my coworkers could tell me that I tend to lean forward at my desk, but I wouldn't have realized to what extent. I've often tried to engage my core muscles while sitting to improve my posture, but if LUMO is to be trusted, I was doing it all wrong.

LUMO isn't completely useless without the app, since it still vibrates when your posture falls out of line. However, I think it's best for someone to use both, especially in the early stages.

It took a few relapses for me to figure out how to sit at my desk properly — LUMO would vibrate, and I would try again to assume a comfortable yet correct sitting posture. I needed to scoot my hips all the way to the back of my chair (earlier, I'd been perched on the edge) and then pull my chair all the way in, so my ribs grazed the desk. This seemed to ensure the correct pelvic tilt, but also that I didn't lean too far forward or backward.

Once home, I continued to wear LUMO while making dinner. This entailed a bit of bending over to get a pot, reaching up to the top shelf, and other things LUMO didn't seem to like. I wondered if I should just drop the device for this portion of my day, or if these outlying activities could even be done with LUMO-approved posture.

Since my next task was to watch a few episodes of Orange Is the New Black, I made an executive decision that LUMO had no place in my time of leisure.

Day Two

The LUMO app provides an ongoing score, and as a beginner, I received an initial goal of 40 (the LUMO community's average was 50). Early on Day Two, my score was 86, up from 57 the day prior. I was winning. I was putting the lessons from Day One to good use — lower back against the back of the chair, pulled all the way in to my desk, and holding very, very still.

Around noon, I noticed my back was a bit sore — perhaps the muscles I used to hold good posture hadn't been utilized in awhile, and now they were reacting to sudden exertion.

Soon it occurred to me that I was personifying LUMO. In my head, we were having a conversation. "LUMO, leave me alone, I'm trying to transcribe an interview here!" I even started comparing my new posture friend to other wearable gadgets. If Google Glass is your awesome personal assistant, then LUMO is the annoying little brother.

Let's just say that, while my posture seemed to be improving, I was less than optimistic about a long-term relationship with this angry device.

Image: Mashable

When I went shopping after work, walking turned out to be an enlightening experience in terms of posture. I almost forgot I was wearing LUMO while walking, and it never vibrated. To be fair, LUMO sits on your waist and really only measures your pelvic tilt, but the literature I've read on posture suggests that fixing pelvic tilt can set you up for success in fixing your shoulder slumping, while the opposite is not true.

While walking didn't upset LUMO, it would vibrate when I stopped at a crosswalk as if on cue. So, to review: Sitting posture, fixed. Walking posture, already perfect. Standing posture, needed improvement.

Day Three

I started my third day of LUMO with a run. I typically run an average of 20 minutes around my neighborhood as a precursor to coffee — steps in my lengthy routine of waking up.

I was especially curious to see what LUMO had to say about my running technique, because I've often felt that running correctly could help me with my posture in general. Unfortunately, LUMO was bouncing around too much to tell me if I was correct. At least, I didn't notice a vibration. Perhaps, if I had the app on my iPhone, I could take a peek mid-run to see how I looked via personal stick figure.

Sitting on a couch with LUMO was especially challenging. The couch was not firm enough to keep my back straight, and I had a tendency to lean forward over my laptop. I eventually got comfortable, and it seemed like the device would let me sit slouched in peace, as long as I didn't move dramatically.

Since I currently live in New York and don't have a car, I wasn't able to test my car posture. However I imagine it would be similar to my desk, and I would need to make some changes to the driver's seat tilt and distance from the steering wheel.

On the subway, I initially blamed LUMO's vibrations on the sudden movements of the train itself. Perkash told me the device has a triaxial accelerometer, which is also found in the Fuelband and really any device that knows when it's horizontal or vertical. I wondered if it were picking up movements that weren't unique to me. But, after finding my standing-at-a-streetlight posture was much worse than my walking posture, I realized my subway posture was indeed among the most abhorrent.

With a reminder from LUMO (I began thinking of the vibrating sensation as a friendly "Doing it wrong! Doing it wrong!") and inspiration from Curry's TED Talk, I've come to visualize myself as Peter Pan in order to break the old habits.

Using LUMO in Moderation

When I met Perkash, I asked if she thought users could graduate out of LUMO — as in, their better postures would become habit and they would no longer need the device. She pointed out that you can simply use it when you need to be especially conscious of posture, such as when you have a big project coming up or you're traveling.

Although I only used LUMO religiously for three days (excluding sleep and a few leisurely activities), I agree — after a few days without the device, I could definitely see muscle memory kicking in, especially at work, where my chair and desk help me find the correct posture. But when I do find myself slouching, I don't know if it's been for five minutes or two hours.

When I went to my volunteer shift at a non-profit bookstore, where I stand for four hours and often notice my back becoming sore about halfway through — I wanted to take LUMO along as a safety net.

However, I did take LUMO to a coffee shop with uncomfortable chairs and wished I hadn't — the shared table was small, I didn't have space to stretch out or cross my legs, and naturally LUMO scolded me the entire time.

I don't expect to wear LUMO all the time, and I think that's OK. Fixing just the eight hours of desk time is a good start.