Reliability and Validity of Ten Consumer Activity Trackers Depend on Walking Speed

Abstract

Test-retest reliability and validity of activity trackers depends on walking speed. In general, consumer activity trackers perform better at an average and vigorous walking speed than at a slower walking speed.

Accuracy of Apple Watch Measurements for Heart Rate and Energy Expenditure in Patients With Cardiovascular Disease: Cross-Sectional Study (Preprint)

“…The ICC was calculated to determine the correlation between Apple Watch measurements and golden standard measurements. Limits for ICC were used as suggested by Fokkema et al [11]: an ICC >0.90 was considered as excellent, 0.75-0.90 as good, 0.60-0.75 as moderate, and <0.60 as low.…”

“…The participant number of 40 patients was determined based on a literature study of comparable studies [5]- [8], [11], [13]. In most of these validation studies of wrist-worn health-tracking devices particpant numbers ranged from 20 to 60 patients.…”

“…Validation studies have been done to evaluate accuracy of HR, EE and other measurements in healthy subjects for a variety of fitness trackers [5][6][7][8][9][10][11][12][13][14][15][16][17]. Boudreaux et al [7] tested eight devices for accuracy of HR and EE measurements on healthy subjects and found that HR accuracy from wearable devices differed at different exercise intensities with an increasing underestimation of HR at higher exercise intensities.…”

Review of Wearable Device Technology and Its Applications to the Mining Industry

“…Some studies in [19][20][21] examined a number of activity trackers and measured their accuracy and reliability at counting steps. The conclusion was that some trackers perform well indoors and provide valid results, whereas others are more suitable for outdoor activities.…”

Assessment of Physical Activity by Wearable Technology During Rehabilitation After Cardiac Surgery: Explorative Prospective Monocentric Observational Cohort Study (Preprint)

“…An important limitation, however, is that commercially available activity trackers are often not thoroughly validated for their accuracy and reliability. Studies showed that step count accuracy is dependent on gait patterns in healthy volunteers [12,13]. In the elderly and the chronically ill, a negative correlation was found between the gait pattern and step count accuracy assessed by other commercially available activity trackers [12,14].…”