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® ActiGraph accelerometer and Google Fit® 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 5min at their fastest speeds, wearing a Cortex Metamax 3B® ergoespirometer, a GT3X® ActiGraph accelerometer, and a smartphone with the Google Fit® 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® ergoespirometer (gold-standard measure). RESULTS: Fair association was found between the energy expenditure values estimated from the combined formula of the ActiGraph GT3X® 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® application and those provided by the gold-standard measure. CONCLUSIONS: The findings demonstrated that both the GT3X®ActiGraph accelerometer and the Google Fit® smartphone application do not provide valid measures of energy expenditure in chronic stroke individuals during fast overground walking.