Reliability and validity of ten consumer activity trackers

Area of Science:

• Wearable technology
• Biomedical engineering
• Human movement analysis

Background:

• Consumer activity trackers aim to increase physical activity.
• Assessing the accuracy of these devices is crucial for their effectiveness.
• This study evaluates ten popular activity trackers.

Purpose of the Study:

• To determine the reliability and validity of ten consumer activity trackers.
• To assess step count measurement accuracy in both controlled and real-world settings.

Main Methods:

• Thirty-three healthy adults performed treadmill walking tests.
• Fifty-six volunteers wore trackers during a typical workday.
• Accuracy was compared against gold-standard systems (Optogait, ActivPAL).

Main Results:

• Most trackers exhibited good test-retest reliability (high ICC scores).
• The Fitbit Zip demonstrated the lowest mean absolute percentage error in both conditions.
• The Nike+ Fuelband showed significant inaccuracies and low reliability (low ICC).

Conclusions:

• The reliability and validity of most consumer activity trackers for step counting are generally good.
• Fitbit Zip is the most accurate tracker evaluated.
• Nike+ Fuelband is not recommended due to poor performance.