Validity of the iPhone M7 motion coprocessor to estimate physical activity during structured and free-living activities in healthy adults
Thomson, Nicola K. and McMichan, Lauren and Macrae, Eilidh and Baker, Julien S. and Muggeridge, David J. and Easton, Chris (2021) Validity of the iPhone M7 motion coprocessor to estimate physical activity during structured and free-living activities in healthy adults. Journal for the Measurement of Physical Behaviour, 4 (3). 212–219. ISSN 2575-6613 (https://doi.org/10.1123/jmpb.2020-0067)
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Abstract
Modern smartphones such as the iPhone contain an integrated accelerometer, which can be used to measure body movement and estimate the volume and intensity of physical activity. Objectives: The primary objective was to assess the validity of the iPhone to measure step count and energy expenditure during laboratory-based physical activities. A further objective was to compare free-living estimates of physical activity between the iPhone and the ActiGraph GT3X+ accelerometer. Methods: Twenty healthy adults wore the iPhone 5S and GT3X+ in a waist-mounted pouch during bouts of treadmill walking, jogging, and other physical activities in the laboratory. Step counts were manually counted, and energy expenditure was measured using indirect calorimetry. During two weeks of free-living, participants (n = 17) continuously wore a GT3X+ attached to their waist and were provided with an iPhone 5S to use as they would their own phone. Results: During treadmill walking, iPhone (703 ± 97 steps) and GT3X+ (675 ± 133 steps) provided accurate measurements of step count compared with the criterion method (700 ± 98 steps). Compared with indirect calorimetry (8 ± 3 kcal·min−1), the iPhone (5 ± 1 kcal·min−1) underestimated energy expenditure with poor agreement. During free-living, the iPhone (7,990 ± 4,673 steps·day−1) recorded a significantly lower (p < .05) daily step count compared with the GT3X+ (9,085 ± 4,647 steps·day−1). Conclusions: The iPhone accurately estimated step count during controlled laboratory walking but recorded a significantly lower volume of physical activity compared with the GT3X+ during free-living.
ORCID iDs
Thomson, Nicola K., McMichan, Lauren ORCID: https://orcid.org/0000-0003-0238-0433, Macrae, Eilidh, Baker, Julien S., Muggeridge, David J. and Easton, Chris;-
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Item type: Article ID code: 78103 Dates: DateEvent30 September 2021Published25 June 2021Published Online24 March 2021AcceptedSubjects: Medicine > Public aspects of medicine > Personal health and hygiene, including exercise, nutrition Department: Faculty of Humanities and Social Sciences (HaSS) > Psychological Sciences and Health > Physical Activity for Health Depositing user: Pure Administrator Date deposited: 08 Oct 2021 15:00 Last modified: 12 Dec 2024 11:37 Related URLs: URI: https://strathprints.strath.ac.uk/id/eprint/78103