Estimating the physical activity with smartphones: Analysis of the device position and comparison with GT3X+ actigraph

Abstract

Nowadays there are commercial devices such as the GT3X+ that can analyze the performance of those who practice some kind of sport, but these devices tend to be rather expensive and complex to use. The objectives of this research are: i) to study the correlation between the measurements of the physical activity with the smartphone and a dedicated accelerometer GT3X+ through the calculation of the counts, ii) to analyze the influence of the position of the smartphone and iii) compare several methods to calculate the energy expenditure trough the counts. Nine volunteers participated in an experiment. They performed different physical activities carrying a smartphone in the right pocket and another one in the hip, together with the GT3X+. The results obtained show a high correlation between the GT3X+ and smartphones for the different types of training (hip and pocket). However the result of the ANOVA indicates that there is no significant difference between the positions of the smartphone.