TY  - JOUR
AU  - Daryabeygi-Khotbehsara, Reza
AU  - Rawstorn, Jonathan C
AU  - Dunstan, David W
AU  - Shariful Islam, Sheikh Mohammed
AU  - Abdelrazek, Mohamed
AU  - Kouzani, Abbas Z
AU  - Thummala, Poojith
AU  - McVicar, Jenna
AU  - Maddison, Ralph
PY  - 2024
DA  - 2024/1/24
TI  - A Bluetooth-Enabled Device for Real-Time Detection of Sitting, Standing, and Walking: Cross-Sectional Validation Study
JO  - JMIR Form Res
SP  - e47157
VL  - 8
KW  - activity tracker
KW  - algorithms
KW  - deep neural network
KW  - machine learning
KW  - real-time data
KW  - Sedentary behaviOR Detector
KW  - sedentary behavior
KW  - SORD
KW  - standing
KW  - validation
KW  - walking
KW  - wearables
AB  - Background: This study assesses the accuracy of a Bluetooth-enabled prototype activity tracker called the Sedentary behaviOR Detector (SORD) device in identifying sedentary, standing, and walking behaviors in a group of adult participants. Objective: The primary objective of this study was to determine the criterion and convergent validity of SORD against direct observation and activPAL. Methods: A total of 15 healthy adults wore SORD and activPAL devices on their thighs while engaging in activities (lying, reclining, sitting, standing, and walking). Direct observation was facilitated with cameras. Algorithms were developed using the Python programming language. The Bland-Altman method was used to assess the level of agreement. Results: Overall, 1 model generated a low level of bias and high precision for SORD. In this model, accuracy, sensitivity, and specificity were all above 0.95 for detecting sitting, reclining, standing, and walking. Bland-Altman results showed that mean biases between SORD and direct observation were 0.3% for sitting and reclining (limits of agreement [LoA]=–0.3% to 0.9%), 1.19% for standing (LoA=–1.5% to 3.42%), and –4.71% for walking (LoA=–9.26% to –0.16%). The mean biases between SORD and activPAL were –3.45% for sitting and reclining (LoA=–11.59% to 4.68%), 7.45% for standing (LoA=–5.04% to 19.95%), and –5.40% for walking (LoA=–11.44% to 0.64%). Conclusions: Results suggest that SORD is a valid device for detecting sitting, standing, and walking, which was demonstrated by excellent accuracy compared to direct observation. SORD offers promise for future inclusion in theory-based, real-time, and adaptive interventions to encourage physical activity and reduce sedentary behavior. 
SN  - 2561-326X
UR  - https://formative.jmir.org/2024/1/e47157
UR  - https://doi.org/10.2196/47157
UR  - http://www.ncbi.nlm.nih.gov/pubmed/38265864
DO  - 10.2196/47157
ID  - info:doi/10.2196/47157
ER  -