Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data

Wearable accelerometers record physical activity with high resolution, potentially capturing the rich details of behaviour changes and habits. Detecting these changes as they emerge is valuable information for any strategy that promotes physical activity and teaches healthy behaviours or habits. Ind...

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Main Authors: Claudio Diaz, Corinne Caillaud, Kalina Yacef
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/22/21/8255
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author Claudio Diaz
Corinne Caillaud
Kalina Yacef
author_facet Claudio Diaz
Corinne Caillaud
Kalina Yacef
author_sort Claudio Diaz
collection DOAJ
description Wearable accelerometers record physical activity with high resolution, potentially capturing the rich details of behaviour changes and habits. Detecting these changes as they emerge is valuable information for any strategy that promotes physical activity and teaches healthy behaviours or habits. Indeed, this offers the opportunity to provide timely feedback and to tailor programmes to each participant’s needs, thus helping to promote the adherence to and the effectiveness of the intervention. This article presents and illustrates U-BEHAVED, an unsupervised algorithm that periodically scans step data streamed from activity trackers to detect physical activity behaviour changes to assess whether they may become habitual patterns. Using rolling time windows, current behaviours are compared with recent previous ones, identifying any significant change. If sustained over time, these new behaviours are classified as potentially new habits. We validated this detection algorithm using a physical activity tracker step dataset (N = 12,798) from 79 users. The algorithm detected 80% of behaviour changes of at least 400 steps within the same hour in users with low variability in physical activity, and of 1600 steps in those with high variability. Based on a threshold cadence of approximately 100 steps per minute for standard walking pace, this number of steps would suggest approximately 4 and 16 min of physical activity at moderate-to-vigorous intensity, respectively. The detection rate for new habits was 80% with a minimum threshold of 500 or 1600 steps within the same hour in users with low or high variability, respectively.
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spelling doaj.art-1f8986730f0449dfa224724f40aff33e2023-11-24T06:45:10ZengMDPI AGSensors1424-82202022-10-012221825510.3390/s22218255Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer DataClaudio Diaz0Corinne Caillaud1Kalina Yacef2School of Computer Science, The University of Sydney, Sydney, NSW 2006, AustraliaBiomedical Informatics and Digital Health, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, AustraliaSchool of Computer Science, The University of Sydney, Sydney, NSW 2006, AustraliaWearable accelerometers record physical activity with high resolution, potentially capturing the rich details of behaviour changes and habits. Detecting these changes as they emerge is valuable information for any strategy that promotes physical activity and teaches healthy behaviours or habits. Indeed, this offers the opportunity to provide timely feedback and to tailor programmes to each participant’s needs, thus helping to promote the adherence to and the effectiveness of the intervention. This article presents and illustrates U-BEHAVED, an unsupervised algorithm that periodically scans step data streamed from activity trackers to detect physical activity behaviour changes to assess whether they may become habitual patterns. Using rolling time windows, current behaviours are compared with recent previous ones, identifying any significant change. If sustained over time, these new behaviours are classified as potentially new habits. We validated this detection algorithm using a physical activity tracker step dataset (N = 12,798) from 79 users. The algorithm detected 80% of behaviour changes of at least 400 steps within the same hour in users with low variability in physical activity, and of 1600 steps in those with high variability. Based on a threshold cadence of approximately 100 steps per minute for standard walking pace, this number of steps would suggest approximately 4 and 16 min of physical activity at moderate-to-vigorous intensity, respectively. The detection rate for new habits was 80% with a minimum threshold of 500 or 1600 steps within the same hour in users with low or high variability, respectively.https://www.mdpi.com/1424-8220/22/21/8255behaviour changesphysical activityunsupervised learningactivity trackeraccelerometer
spellingShingle Claudio Diaz
Corinne Caillaud
Kalina Yacef
Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data
Sensors
behaviour changes
physical activity
unsupervised learning
activity tracker
accelerometer
title Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data
title_full Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data
title_fullStr Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data
title_full_unstemmed Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data
title_short Unsupervised Early Detection of Physical Activity Behaviour Changes from Wearable Accelerometer Data
title_sort unsupervised early detection of physical activity behaviour changes from wearable accelerometer data
topic behaviour changes
physical activity
unsupervised learning
activity tracker
accelerometer
url https://www.mdpi.com/1424-8220/22/21/8255
work_keys_str_mv AT claudiodiaz unsupervisedearlydetectionofphysicalactivitybehaviourchangesfromwearableaccelerometerdata
AT corinnecaillaud unsupervisedearlydetectionofphysicalactivitybehaviourchangesfromwearableaccelerometerdata
AT kalinayacef unsupervisedearlydetectionofphysicalactivitybehaviourchangesfromwearableaccelerometerdata