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

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.

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).

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.

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.