Table 6 Strategies to improve the activity tracker accuracy for steps, distance, physical activity, energy expenditure, and sleep

Wear the tracker in the same position each day

While wearing the activity tracker in the same position daily may be obvious for the wrist-based trackers, those worn on a pocket, bra, or hip could vary in accuracy depending on location. Trackers are more accurate when worn close to the body^a. For free-living research studies, the wearing location should be standardized and communicated to participants.

^a http://help.fitbit.com/articles/en_US/Help_article/How-do-I-wear-my-Zip/

Enter your details and sync

At initial set-up, users should accurately enter height, weight, gender, and age into the application and sync it to the tracker. For example, these characteristics, as well as heart rate if available, are used by the Fitbit to calculate energy expenditure^b. Related to this, if body weight meaningfully changes, then updating the tracker with the new weight would be important.

^b http://help.fitbit.com/articles/en_US/Help_article/How-does-Fitbit-know-how-many-calories-I-ve-burned

For wrist-worn trackers, indicate if wearing it on the dominant or non-dominant side

In the software set-up, indicate if possible whether the wrist-worn tracker is being worn on the dominant or non-dominant hand. For Jawbone, trackers worn on the non-dominant wrist may be more accurate^c, probably because the non-dominant hand is less active than the dominant hand, so it provides a better representation of overall body movement. Fitbit indicates that using the non-dominant hand setting increases sensitivity of step counting and can be used if the tracker is under counting steps^d.

^c https://jawbone.com/up/faq

^d http://help.fitbit.com/articles/en_US/Help_article/How-accurate-is-my-Surge

Calibrate stride length

Calibrating stride length may improve distance measures. In our review, only one study indicated that this was performed [34]. Fitbit indicates a default stride length is used otherwise, based on height and gender^e. Jawbone also provides information for calibration^f.

^d http://help.fitbit.com/articles/en_US/Help_article/How-do-I-measure-and-adjust-my-stride-length

^e https://help.jawbone.com/articles/en_US/PKB_Article/424

Use add-on features and obtain updates

Using add-on features and obtaining updates might become more important since future iterations of algorithms to calculate physical activity or energy expenditure may use new features, such as heart rate and respiration. For example, Fitbit indicates that trackers with heart rate better recognize “active minutes” for physical activities that do not incorporate stepping, such as weight lifting or rowing^e.

^f https://help.fitbit.com/articles/en_US/Help_article/What-are-very-active-minutes/

Add more information via the diary or journal function

Providing information to the tracker on the specific physical activity being performed can help the tracker learn what activities look like for the individual. This is particularly important if the algorithms used by the activity tracker rely on machine learning techniques.

Interact with the sleep mode settings

Interacting with the sleep mode settings may help the tracker learn if the user is sleeping, napping, or awake. Fitbit indicates that the normal mode counts significant movements as being awake and is appropriate for most users, while the sensitive setting will record nearly all movements as time awake^f.

^g http://help.fitbit.com/articles/en_US/Help_article/Sleep-tracking-FAQs#Whatisthedifference