Smartphones apps equal to fitness wearables for step tracking, study says

Posted:
in General Discussion edited February 2015
Consumers searching for the best way to automatically log their daily activity may need to look no farther than the App Store, as a new study from the University of Pennsylvania shows that data collected by dedicated fitness wearables is generally no more accurate than that from a smartphone kept in a pocket.



"In this study, we wanted to address one of the challenges with using wearable devices: they must be accurate," said Penn medical student and lead study author Meredith A. Case, BA. "After all, if a device is going to be effective at monitoring -- and potentially changing -- behavior, individuals have to be able to trust the data. We found that smartphone apps are just as accurate as wearable devices for tracking physical activity."

To gather data, researchers loaded 14 participants up with 6 wearable devices: a Digi-Walker SW-200 pedometer, Fitbit's Zip and One clip-on trackers and Flex wristband, Jawbone's Up24, and Nike's Fuelband. In addition, an iPhone 5s sat in one pocket running the Fitbit app, Withings's Health Mate app, and ProtoGeo Oy's Moves app, while a Samsung Galaxy S4 sat in the other pocket running Moves on Android.

Each participant was then asked to walk on a treadmill at 3 miles per hour, twice each for 500 steps and 1,500 steps. Data collected from the smartphone apps had a range of -6.7 percent to 6.2 percent relative difference from the number of steps researchers observed the participants taking, while the wearables came in with a range of -22.7 percent to -1.5 percent.

According to the data, Nike's Fuelband was sometimes wildy off; Jawbone's Up24 and Fitbit's Flex booked the second- and third-largest deviations. Fitbit's Zip and One were nearly perfect.

Apple, of course, offers solutions in both categories. The iPhone 5s and iPhone 6 series contain built-in M-series motion coprocessors which constantly monitor device motion and feed step data to the iOS Health app.

Apple has also touted the health and fitness abilities of the forthcoming Apple Watch. That device includes a built-in accelerometer for tracking steps and total body movements.
«1

Comments

  • Reply 1 of 24
    the absolute numbers are not very important, as long as one keeps using the same device its the relative numbers one uses to determine progress
  • Reply 2 of 24
    1) I'd classify this as Fitbit being the best option of the bunch, although their Flex leaves something to be desired. Is that their oldest model?

    2) I'd like to see movement not on a treadmill to see how that affects the accuracy of the results.
  • Reply 3 of 24
    Movement in real world instead of treadmill would be interesting to test.

    1. In real world the running tends to be a little more irregular

    2. How well does the GPS readings of distances work in all of these.
  • Reply 4 of 24

    The issue I've had with the 6 Plus is that, if I have it on me and am rocking on my La-z-boy, it counts each rock as a step. That means I can rack up the step count by just lazing around. 

     

    Of course, there is probably no way currently to avoid that, but it would be nice if there was a way to toggle the recording of steps.

  • Reply 5 of 24
    The issue I've had with the 6 Plus is that, if I have it on me and am rocking on my La-z-boy, it counts each rock as a step. That means I can rack up the step count by just lazing around. 

    Of course, there is probably no way currently to avoid that, but it would be nice if there was a way to toggle the recording of steps.

    Not really. You'd forget to turn it back on and lose step data all the time. Far better solution is for you to set it on the coffee table. Problem solved.
  • Reply 6 of 24

    The problem with step counting via the iPhone is that the charge can't last for a whole day. So when you need to recharge, it will be out of your pocket and stationary on a desk. Your steps will then no longer be counted.

     

    At least with wearables like the Apple Watch, the battery is expected to last a day, so your steps will be counted all the time, giving you a more accurate picture of how many steps you really took over the course of one day. You take it off for recharging at night, a time when you're most definitely not taking any more steps (unless you're sleepwalking, that is).

  • Reply 7 of 24
    Boom.

    It was nice knowing you, Apple Watch.
  • Reply 8 of 24
    Boom.

    It was nice knowing you, Apple Watch.

    Within 6 months the same study will be updated showing their current research is no longer valid.
  • Reply 9 of 24
    bageljoeybageljoey Posts: 1,937member
    The issue I've had with the 6 Plus is that, if I have it on me and am rocking on my La-z-boy, it counts each rock as a step. That means I can rack up the step count by just lazing around. 

    Of course, there is probably no way currently to avoid that, but it would be nice if there was a way to toggle the recording of steps.

    I haven't really followed these tracking devices much, but I always assumed that the dedicated bands collected more than just steps. I assumed that they would combine that info with heart rate or temperature or something to get more meaningful data.

    As a teacher in a middle school, I can always tell when the kids are wearing those little clip on pedometers (they get them with physical education classes at some point every year). They flip their wrist or ankle constantly during class trying to get the highest step count in their class. "I'm at 3000 steps already!!"

    If all these $100 bands don't collect better info than a $4 clip on, I would be greatly disappointed! Would it be wrong to expect the Apple Watch to mix other data in with its "step" count?
  • Reply 10 of 24
    solipsismy wrote: »
    1) I'd classify this as Fitbit being the best option of the bunch, although their Flex leaves something to be desired. Is that their oldest model?

    2) I'd like to see movement not on a treadmill to see how that affects the accuracy of the results.

    That was my conclusion, to.

    If I were in the market for a wearable, I would probably get the Fitbit.
  • Reply 11 of 24
    The issue I've had with the 6 Plus is that, if I have it on me and am rocking on my La-z-boy, it counts each rock as a step. That means I can rack up the step count by just lazing around. 

    Of course, there is probably no way currently to avoid that, but it would be nice if there was a way to toggle the recording of steps.

    Indeed.

    I don't think any device is going to be 100% accurate in the real world, because no device can truly know what is a step at the moment; they just go by movement.

    I used to use Moves, but found it wildly inaccurate. I was once in a taxi, and my step count was increasing rapidly! I have been using Pacer for a couple of years, and find it great. It still picks up some movements as steps, but I think it's generally pretty accurate.
  • Reply 12 of 24
    nikmanshah wrote: »
    The problem with step counting via the iPhone is that the charge can't last for a whole day. So when you need to recharge, it will be out of your pocket and stationary on a desk. Your steps will then no longer be counted.

    At least with wearables like the Apple Watch, the battery is expected to last a day, so your steps will be counted all the time, giving you a more accurate picture of how many steps you really took over the course of one day. You take it off for recharging at night, a time when you're most definitely not taking any more steps (unless you're sleepwalking, that is).

    I only have an iPhone 5, but use Pacer, a steps counter, all day. It runs in the background and uses GPS, but I still get through the day on one charge, unless I'm using my phone heavily, in which case I use a Mophie key ring charger to boost it 50%. I rarely need it, though.
  • Reply 13 of 24

    The Fitbit Flex is worn around the wrist, whereas the other two are worn close to your body. The accelerometer data collected close to your trunk is much easier to parse into a correct step count compared to data captured at the end of your arm, which moves in a number of arbitrary ways. That's why wrist worn activity trackers will always perform worse in terms of step counting.

     

    If worn in a pocket snug to the body, like in this study, the smartphone should be close to the clip-on trackers in its accuracy. If smartphones are worn on an armband or inside pocket or bag where it can bounce around, data will be much less correct.

  • Reply 14 of 24



    1) The real world results are likely proportional to this test. There's no reason to believe that the trackers that performed badly in this controlled test would be better in general use. The wrist worn trackers would likely be even more off when tracking running for example, due to more pronounced arm movement, which is hard to interpret correctly.

     

    2)  There were no GPS data or applications using GPS included in these tests. The whole point of adding a motion coprocessor - like Apple's M7 to a smartphone is that it is always on, tracking and storing your activity while using negligible amounts of energy. Using GPS for tracking will quickly drain your battery, and will in many cases be less accurate. Some of the best sports apps can use and combine both data sources to correct for e.g. GPS dropouts.

  • Reply 15 of 24
    "The problem with step counting via the iPhone is that the charge can't last for a whole day."

    Well, that's nonsense. That's why they have the co-prosessor - it's always counting steps with no major affect on the battery life.
  • Reply 16 of 24
    paxmanpaxman Posts: 4,670member
    Quote:

    Originally Posted by Benjamin Frost View Post



    If I were in the market for a wearable, I would probably get the Fitbit.

     

    That would depend on what tasks you wanted your wearable to perform, no? If I was in the market for a wearable I'd use my iPhone and wait for the ?watch because I am biased like hell.

  • Reply 17 of 24
    It seems pretty clear that there's a trend here: clip-on devices are the most accurate, and wrist-worn trackers are less accurate.

    The downside is that clip-on trackers are far easier to lose or put through the laundry. Accuracy doesn't mean much when the device has been dropped in a parking lot or is tumbling around in the dryer.
  • Reply 18 of 24
    Quote:

    Originally Posted by Paul94544 View Post



    the absolute numbers are not very important, as long as one keeps using the same device its the relative numbers one uses to determine progress

     

    In theory that sounds good, but the devices need to be somewhat consistent unto themselves for that to really be true. If you look at the graph, some of the solutions have a huge margin of error. I agree with you for the devices with the shortest bars. It isn't about accuracy so much as consistency so you can effectively measure progress. But who wants to push themselves harder than they ever have to get a false reading of progress that is off by a dramatic amount.

     

    Just look at the Nike Fuelband on the 500 step graph. You walk the same 500 steps and it reads 500 one day and about 260 the next. That is just too much variation for someone to gauge how they are progressing day after day. On the 1500 step test it was 1500 or 800? Wow, this study should kill their sales. 

  • Reply 19 of 24
    I can tell you Apple health app is not accurate on tracking steps and distance traveled and such.

    I also have to agree there are some very good health tracking apps in the app store. I down loaded few and have been playing with them to see how good thay are. The good one now require a yearly subscription, which I am being to hate, why must have have to keep paying for an app yr after yr just to use it.

    Apple own health app is about 50% wrong. Every morning I take the dog for a long walk and I know the distance we go since we been doing it for 4 yrs and the health apps always says we have gone 50% further than we did. Some other apps I have download are right on. The difference I notice is the apps which are right on use the GPS to track your motion. The health app and other motion tracker app which are usually wrong are using apple motion engine chip. I think the motion engine can be accurate, but it needs to be calibrated to your steps and such and it most likely depends on where the phone is mounted. In my case I usually have the phone in my pocket.

    Since the Watch is going to use the same motion engine as the iphone 6 it too most likely will need to be calibrated in order to provide you accurate data.
  • Reply 20 of 24
    Quote:

    Originally Posted by BestKeptSecret View Post

     

    The issue I've had with the 6 Plus is that, if I have it on me and am rocking on my La-z-boy, it counts each rock as a step. That means I can rack up the step count by just lazing around. 

     

    Of course, there is probably no way currently to avoid that, but it would be nice if there was a way to toggle the recording of steps.




    That Moves app I like but it did tell me I did 11KMs of cycling when I hadn't left my desk. I have fidgety leg and it picked it up.

     

    That being said though, that's the point of these apps. To track movement not just steps. That's why I'm really looking forward to the Apple Watch because all the sensors track every movement you do. A pedometer can only track steps but that's not what the fitness experts are trying to get us to do.

     

    One app I'm really liking at the moment is Human. It's like Moves but it doesn't really track steps per se it tracks all movement you do. It's a really nice little app.

Sign In or Register to comment.