Step-count outcomes of 13 different activity trackers: Results from laboratory and free-living experiments

• Published in: Gait & posture Vol. 98; pp. 24 - 33
• Main Authors: Nakagata, Takashi, Murakami, Haruka, Kawakami, Ryoko, Tripette, Julien, Nakae, Satoshi, Yamada, Yosuke, Ishikawa-Takata, Kazuko, Tanaka, Shigeho, Miyachi, Motohiko
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01-10-2022
• Subjects: Accelerometer; Accelerometry - methods; Actigraphy; Adult; Exercise; Fitness Trackers; Humans; Middle Aged; Pedometer; Physical activity; Reproducibility of Results; Steps; Validity; Wearable Electronic Devices; Young Adult; Steps; SD; Validity; SEE; Physical activity; AMED; JIS; ICC; Accelerometer; Pedometer; DLW
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2022.08.004

Many activity trackers have been developed, but steps can still be inconsistent from one monitor to another.
What are the differences and associations between the steps of 13 selected consumer-based and research-grade wearable devices during 1 standardized day in a metabolic chamber and 15-day free-living trials?
In total, 19 healthy adults between 21 and 50 years-old participated in this study. Participants were equipped with 12 accelerometer-based active trackers and one pedometer (Yamasa) in order to monitor the number of steps per day. The devices were worn on the waist (ActiGraph, Omron, Actimarker, Lifedorder, Withings, and Yamasa) or non-dominant wrist (Fitbit, Garmin, Misfit, EPSON, and Jawbone), or placed in a pocket (Omron CaloriScan, and TANITA). Participants performed structured activities over a 24 h period in a chamber (Standardized day), and steps were monitored in the same participants in free-living trials for 15 successive days using the same monitors (free-living days).
When the 13 monitors were ranked by their steps, waist-worn ActiGraph was located at the center (7th) of the monitors both in the Standardized (12,252 ± 598 steps/day, mean ± SD) and free-living days (9295 ± 4027 steps/day). The correlation between the accelerometer-based devices was very high (r = 0.87–0.99). However, the steps of Yamasa was significantly lower in both trials than ActiGraph. The wrist-worn accelerometers had significantly higher steps than other devices both trials (P < 0.05). The differences between ActiGraph and Actimarker or Lifecorder was less than 100 steps/day in the Standardized day, and the differences between ActiGraph and Active Style Pro was less than 100 steps/day in the free-living days. Regression equation was also performed for inter-device compatibility.
Step obtained from the wrist-worn, waist-worn, and pocket-type activity trackers were significantly different from each other but still highly correlated in free-living conditions.
•Daily step count is one of the simplest indices of daily physical activity.•We examined the difference and associations among step counts during in a metabolic chamber and 15-day free-living trials.•Steps from 13 selected consumer-based and research-grade wearable devices varied (maximum range, 2000–2500) in both trials.•But, step counts obtained from 13 wearable devices were highly correlated with each other in free-living trail.•Researchers and clinicians should be aware of the current differences.