Wearable activity trackers

Just a few months back, Dan got himself the Fitbit Ultra, that tracked how many steps he did, and from I can see on the product website, it also tracks distance, sleep, calories burned, allows you to log your food intake, and since then they also added a new feature that tracks stairs climbing. Its like a supercharged pedometer.

Now other than Fitbit, many other sports, health and start-up companies have recently jumped onto the bandwagon of making Wearable Activity Trackers (WAT). Not just tracking sports activities like running or cycling where you use GPS to track your location, speed and altitude; but activity in general. Its almost like writing your diary or journal at the end of each day, and recording every single (physical) activity you did, minus the emotions; and the main motivation for using these devices: to lose weight, keep fit and stay healthy. Since I am not having any other projects on hand at the moment, I decided to do a bit of investigation, online. I’m sure the list is not exhaustive but these are the more popular ones that are in the market (or coming soon into the market):-  Nike+ Fuel band, Jawbone Up, LarkBasis, BodyMedia Fit, Sqord Powerband, Fitbit, & Misfit Shine.


So these WAT typically have three common features:

  1. They are wearable (obviously),
  2. They have sensor/s on them, and
  3. They have processors with some smart algorithm that makes sense out of the sensor data.


Wearable/Design. In terms of being wearable, they can either be worn on your wrist, which seems to be the most common, or worn like an armband or clipped on your clothing or shoes or bike. Some of them display figures and stats while some just have little LED lights that show how you are progressing on your activities. But all of them are designed to look aesthetically pleasing since it has to been worn on people during most of the waking hours.

Sensors/Trackers. How do they track or measure activities? Although not all companies provide that information, but logically these devices would have accelerometers built in to capture movement data – walking, running, jumping or sleeping. They possibly have GPS modules and Altimeters that give you location and altitude data. BodyMedia and Basis also monitors your perspiration, skin temperature and heart rate (only Basis), because you could be doing Yoga and even though there isn’t too much movement involved, it still works up a sweat.

Algorithms/Insights. But having all that raw data mentioned above can be a bit of a pain if it doesn’t mean anything. So they need some form of algorithm (decision or machine learning) that deciphers the data. Using the acceleration data (either single axis or resultant of three axes), counting steps could be as straightforward as counting the number of peaks from the acceleration signal. Estimating your stride length could give you distance which could also be verified with positioning data from GPS. If combined with an altimeter, it would be able to tell if you are climbing stairs or going uphill. Then the physiological data coupled with movement data probably provides input for calculating calories burned. The ‘tricky’ bit is identifying different physical activities. Lark can differentiate between walking and running, which is quite straightforward in my opinion (see figure below). Shine on the other hand, seems to be able to differentiate bike pedaling, swimming and running. That is quite intriguing and I am curious how they do it. A ‘smart’ way of doing it is to simply track all different activities using an overall activity score. Nike uses the NikeFuel, which they say is the universal metric of activity. If you check their website, it mentions a ‘sports-tested accelerometer‘, true story. I think they probably mean the accelerometer is suitable for measuring movements in sports.


Records. Anyway all that processed information is then stored in their own database system where you can review your activities last week or month or year (on your smart phone or computer) and get an idea of how well or poorly you have progressed in your quest for good health. Then lastly, to spur you on, there is the whole connection with social media and gamification that allows you to compare your performance with your friends or even some sports celebrity.

Is this effective? Well a study showed that among a group of overweight people, half of the group that used a tracking system lost more weight than the other half that didn’t. A guy who found out he had diabetes turned to using these devices and a host of other health monitoring equipment, and actually managed to ‘save’ himself after 6 months of activity tracking. So it works. Although there are some who think constant tracking isn’t really necessarily the best, and some who think there is still room for  improvement (maybe that’s why new gadgets keep appearing), such as making ALL the data interoperable and having a unified electronic health record.

So what next? For the sports nut or health conscious consumer, the bottom line is still: are you willing to pay around $150 – 200 to track your life? For the engineers or developers, if you see more opportunities in this area, some of these companies (like Shine) offer APIs for their devices, and Nike has even come up with a program to support companies who have interesting ideas on how to promote active living. Most importantly, you will get to work with the ‘sports-tested accelerometer‘! How cool is that? Maybe I should sign up for that…

This entry was posted in Sports technology and tagged , on by .

About Julian Chua

Mechanical engineer. Found an interest in applying engineering and technology in sports. Worked for a bit in manufacturing & product development. Dabbled in some electronics and programming. Miraculously got into a PhD along the way. Finds research interesting but leans towards the application side of things. Generally enjoys developing solutions or trouble-shooting issues in technology for sports applications. Now also attempting to combine product design & development with sports/medical technology. Runs or kayaks in spare time. Tweets as @julrx.

One thought on “Wearable activity trackers

  1. Pingback: Crowdsourcing Sports Innovation | Sports Technology Blog – Enabling technologies for sport and health

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