Validity of the accelerometer and smartphone application in estimating energy expenditure in individuals with chronic stroke

Objective: To examine the concurrent validity of the GT3X (R) ActiGraph accelerometer and Google Fit (R) smartphone application in estimating energy expenditure in people who had suffered a stroke, during fast overground walking. Methods: Thirty community-dwelling stroke individuals walked on a 10-meter hallway over 5 min at their fastest speeds, wearing a Cortex Metamax 3B (R) ergoespirometer, a GT3X (R) ActiGraph accelerometer, and a smartphone with the Google Fit (R) application. Pearson correlation coefficients were calculated to verify the associations between measures of energy expenditure, in kilocalories (kcal), estimated by both devices and those obtained with the Cortex Metamax 3B (R) ergoespirometer (gold-standard measure). Results: Fair association was found between the energy expenditure values estimated from the combined formula of the ActiGraph GT3X (R) and those obtained with the gold-standard measure (r = 0.37; p = 0.04). No significant associations were found between the energy expenditure values estimated by the Google Fit (R) application and those provided by the gold-standard measure. Conclusions: The findings demonstrated that both the GT3X (R) ActiGraph accelerometer and the Google Fit (R) smartphone application do not provide valid measures of energy expenditure in chronic stroke individuals during fast overground walking. (C) 2018 Associacao Brasileira de Pesquisa e Pos-Graduacao em Fisioterapia. Published by Elsevier Editora Ltda. All rights reserved.