TitleA catalog of validity indices for step counting wearable technologies during treadmill walking: the CADENCE-Kids study.
Publication TypeJournal Article
Year of Publication2021
AuthorsGould, ZR, Mora-Gonzalez, J, Aguiar, EJ, Schuna, Jr, JM, Barreira, TV, Moore, CC, Staudenmayer, J, Tudor-Locke, C
JournalInt J Behav Nutr Phys Act
Date Published07/2021
KeywordsActigraphy, Adolescent, Adult, Catalogs as Topic, Child, Cross-Sectional Studies, Female, Humans, Male, Reproducibility of Results, Walking, Wearable Electronic Devices, Young Adult

BACKGROUND: Wearable technologies play an important role in measuring physical activity (PA) and promoting health. Standardized validation indices (i.e., accuracy, bias, and precision) compare performance of step counting wearable technologies in young people.

PURPOSE: To produce a catalog of validity indices for step counting wearable technologies assessed during different treadmill speeds (slow [0.8-3.2 km/h], normal [4.0-6.4 km/h], fast [7.2-8.0 km/h]), wear locations (waist, wrist/arm, thigh, and ankle), and age groups (children, 6-12 years; adolescents, 13-17 years; young adults, 18-20 years).

METHODS: One hundred seventeen individuals (13.1 ± 4.2 years, 50.4% female) participated in this cross-sectional study and completed 5-min treadmill bouts (0.8 km/h to 8.0 km/h) while wearing eight devices (Waist: Actical, ActiGraph GT3X+, NL-1000, SW-200; Wrist: ActiGraph GT3X+; Arm: SenseWear; Thigh: activPAL; Ankle: StepWatch). Directly observed steps served as the criterion measure. Accuracy (mean absolute percentage error, MAPE), bias (mean percentage error, MPE), and precision (correlation coefficient, r; standard deviation, SD; coefficient of variation, CoV) were computed.

RESULTS: Five of the eight tested wearable technologies (i.e., Actical, waist-worn ActiGraph GT3X+, activPAL, StepWatch, and SW-200) performed at < 5% MAPE over the range of normal speeds. More generally, waist (MAPE = 4%), thigh (4%) and ankle (5%) locations displayed higher accuracy than the wrist location (23%) at normal speeds. On average, all wearable technologies displayed the lowest accuracy across slow speeds (MAPE = 50.1 ± 35.5%), and the highest accuracy across normal speeds (MAPE = 15.9 ± 21.7%). Speed and wear location had a significant effect on accuracy and bias (P < 0.001), but not on precision (P > 0.05). Age did not have any effect (P > 0.05).

CONCLUSIONS: Standardized validation indices focused on accuracy, bias, and precision were cataloged by speed, wear location, and age group to serve as important reference points when selecting and/or evaluating device performance in young people moving forward. Reduced performance can be expected at very slow walking speeds (0.8 to 3.2 km/h) for all devices. Ankle-worn and thigh-worn devices demonstrated the highest accuracy. Speed and wear location had a significant effect on accuracy and bias, but not precision.

TRIAL REGISTRATION: Clinicaltrials.gov NCT01989104 . Registered November 14, 2013.

Alternate JournalInt J Behav Nutr Phys Act
PubMed ID34271922
PubMed Central IDPMC8283935
Grant ListR21 HD073807 / HD / NICHD NIH HHS / United States
U54 GM104940 / GM / NIGMS NIH HHS / United States
NICHD 1R21HD073807 / NH / NIH HHS / United States
1 U54 GM104940 / GM / NIGMS NIH HHS / United States