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How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities
BACKGROUND: As commercially available activity trackers are being utilized in clinical trials, the research community remains uncertain about reliability of the trackers, particularly in studies that involve walking aids and low-intensity activities. While these trackers have been tested for reliabi...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
JMIR Publications
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5572056/ https://www.ncbi.nlm.nih.gov/pubmed/28801304 http://dx.doi.org/10.2196/mhealth.6321 |
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author | Alinia, Parastoo Cain, Chris Fallahzadeh, Ramin Shahrokni, Armin Cook, Diane Ghasemzadeh, Hassan |
author_facet | Alinia, Parastoo Cain, Chris Fallahzadeh, Ramin Shahrokni, Armin Cook, Diane Ghasemzadeh, Hassan |
author_sort | Alinia, Parastoo |
collection | PubMed |
description | BACKGROUND: As commercially available activity trackers are being utilized in clinical trials, the research community remains uncertain about reliability of the trackers, particularly in studies that involve walking aids and low-intensity activities. While these trackers have been tested for reliability during walking and running activities, there has been limited research on validating them during low-intensity activities and walking with assistive tools. OBJECTIVE: The aim of this study was to (1) determine the accuracy of 3 Fitbit devices (ie, Zip, One, and Flex) at different wearing positions (ie, pants pocket, chest, and wrist) during walking at 3 different speeds, 2.5, 5, and 8 km/h, performed by healthy adults on a treadmill; (2) determine the accuracy of the mentioned trackers worn at different sites during activities of daily living; and (3) examine whether intensity of physical activity (PA) impacts the choice of optimal wearing site of the tracker. METHODS: We recruited 15 healthy young adults to perform 6 PAs while wearing 3 Fitbit devices (ie, Zip, One, and Flex) on their chest, pants pocket, and wrist. The activities include walking at 2.5, 5, and 8 km/h, pushing a shopping cart, walking with aid of a walker, and eating while sitting. We compared the number of steps counted by each tracker with gold standard numbers. We performed multiple statistical analyses to compute descriptive statistics (ie, ANOVA test), intraclass correlation coefficient (ICC), mean absolute error rate, and correlation by comparing the tracker-recorded data with that of the gold standard. RESULTS: All the 3 trackers demonstrated good-to-excellent (ICC>0.75) correlation with the gold standard step counts during treadmill experiments. The correlation was poor (ICC<0.60), and the error rate was significantly higher in walker experiment compared to other activities. There was no significant difference between the trackers and the gold standard in the shopping cart experiment. The wrist worn tracker, Flex, counted several steps when eating (P<.01). The chest tracker was identified as the most promising site to capture steps in more intense activities, while the wrist was the optimal wearing site in less intense activities. CONCLUSIONS: This feasibility study focused on 6 PAs and demonstrated that Fitbit trackers were most accurate when walking on a treadmill and least accurate during walking with a walking aid and for low-intensity activities. This may suggest excluding participants with assistive devices from studies that focus on PA interventions using commercially available trackers. This study also indicates that the wearing site of the tracker is an important factor impacting the accuracy performance. A larger scale study with a more diverse population, various activity tracker vendors, and a larger activity set are warranted to generalize our results. |
format | Online Article Text |
id | pubmed-5572056 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | JMIR Publications |
record_format | MEDLINE/PubMed |
spelling | pubmed-55720562017-09-07 How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities Alinia, Parastoo Cain, Chris Fallahzadeh, Ramin Shahrokni, Armin Cook, Diane Ghasemzadeh, Hassan JMIR Mhealth Uhealth Original Paper BACKGROUND: As commercially available activity trackers are being utilized in clinical trials, the research community remains uncertain about reliability of the trackers, particularly in studies that involve walking aids and low-intensity activities. While these trackers have been tested for reliability during walking and running activities, there has been limited research on validating them during low-intensity activities and walking with assistive tools. OBJECTIVE: The aim of this study was to (1) determine the accuracy of 3 Fitbit devices (ie, Zip, One, and Flex) at different wearing positions (ie, pants pocket, chest, and wrist) during walking at 3 different speeds, 2.5, 5, and 8 km/h, performed by healthy adults on a treadmill; (2) determine the accuracy of the mentioned trackers worn at different sites during activities of daily living; and (3) examine whether intensity of physical activity (PA) impacts the choice of optimal wearing site of the tracker. METHODS: We recruited 15 healthy young adults to perform 6 PAs while wearing 3 Fitbit devices (ie, Zip, One, and Flex) on their chest, pants pocket, and wrist. The activities include walking at 2.5, 5, and 8 km/h, pushing a shopping cart, walking with aid of a walker, and eating while sitting. We compared the number of steps counted by each tracker with gold standard numbers. We performed multiple statistical analyses to compute descriptive statistics (ie, ANOVA test), intraclass correlation coefficient (ICC), mean absolute error rate, and correlation by comparing the tracker-recorded data with that of the gold standard. RESULTS: All the 3 trackers demonstrated good-to-excellent (ICC>0.75) correlation with the gold standard step counts during treadmill experiments. The correlation was poor (ICC<0.60), and the error rate was significantly higher in walker experiment compared to other activities. There was no significant difference between the trackers and the gold standard in the shopping cart experiment. The wrist worn tracker, Flex, counted several steps when eating (P<.01). The chest tracker was identified as the most promising site to capture steps in more intense activities, while the wrist was the optimal wearing site in less intense activities. CONCLUSIONS: This feasibility study focused on 6 PAs and demonstrated that Fitbit trackers were most accurate when walking on a treadmill and least accurate during walking with a walking aid and for low-intensity activities. This may suggest excluding participants with assistive devices from studies that focus on PA interventions using commercially available trackers. This study also indicates that the wearing site of the tracker is an important factor impacting the accuracy performance. A larger scale study with a more diverse population, various activity tracker vendors, and a larger activity set are warranted to generalize our results. JMIR Publications 2017-08-11 /pmc/articles/PMC5572056/ /pubmed/28801304 http://dx.doi.org/10.2196/mhealth.6321 Text en ©Parastoo Alinia, Chris Cain, Ramin Fallahzadeh, Armin Shahrokni, Diane Cook, Hassan Ghasemzadeh. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 11.08.2017. https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR mhealth and uhealth, is properly cited. The complete bibliographic information, a link to the original publication on http://mhealth.jmir.org/, as well as this copyright and license information must be included. |
spellingShingle | Original Paper Alinia, Parastoo Cain, Chris Fallahzadeh, Ramin Shahrokni, Armin Cook, Diane Ghasemzadeh, Hassan How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities |
title | How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities |
title_full | How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities |
title_fullStr | How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities |
title_full_unstemmed | How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities |
title_short | How Accurate Is Your Activity Tracker? A Comparative Study of Step Counts in Low-Intensity Physical Activities |
title_sort | how accurate is your activity tracker? a comparative study of step counts in low-intensity physical activities |
topic | Original Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5572056/ https://www.ncbi.nlm.nih.gov/pubmed/28801304 http://dx.doi.org/10.2196/mhealth.6321 |
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