Affiliations: [a] Instituto de Telecomunicações, University of Beira Interior, Rua Marquês d’Ávila e Bolama, 6201-001 Covilhã, Portugal. E-mails: impires@it.ubi.pt, virginie@it.ubi.pt, ngpombo@ubi.pt, ngarcia@di.ubi.pt | [b] Altranportugal, Lisbon, Portugal. E-mail: ivan.pires@altran.com | [c] ALLab – Assisted Living Computing and Telecommunications Laboratory, Computer Science Department, University of Beira Interior, Covilhã, Portugal | [d] Digital Safety & Security Department, AIT Austrian Institute of Technology, Vienna, Austria. E-mail: mario.drobics@ait.ac.at | [e] Department of Computer Technology, Universidad de Alicante, Spain. E-mail: francisco.florez@ua.es
Abstract: The main goal of this paper consists on the adaption and validation of a method for the measurement of the energy expenditure during physical activities. Sensors available in a mobile device, e.g., a smartphone, a smartwatch, or others, allow the capture of several signals, which may be used to the estimation of the energy expenditure. The adaption consists in the comparison between the units of the data acquired by a tri-axial accelerometer and a mobile device accelerometer. The tests were performed by healthy people with ages between 12 and 50 years old that performed several activities, such as standing, gym (walking), climbing stairs, walking, jumping, running, playing tennis, and squatting, with a mobile device on the waist. The validation of the method showed that the energy expenditure is underestimated and super estimated in some cases, but with reliable results. The creation of a validated method for the measurement of energy expenditure during physical activities capable for the implementation in a mobile application is an important issue for increase the acceptance of the mobile applications in the market. As verified the results obtained are around 124.6 kcal/h, for walking activity, and 149.7 kcal/h, for running activity.
Keywords: Physical exercise, energy expenditure, algorithm, mobile devices, accelerometer
