Google fit smartphone application or Gt3X Actigraph: Which is better for detecting the stepping activity of individuals with stroke? A validity study

To examine the validity of the GT3X® ActiGraph accelerometer and the Google Fit® smartphone application in estimating stepping activity in people with chronic stroke. Thirty-seven stroke survivors walked along a straight, 10 metre hallway over 5 min at their fastest speeds, wearing the GT3X® ActiGraph accelerometer and a smartphone on their paretic lower limb. The criterion-standard measurement made was the actual number of steps, counted by a trained examiner. The mean estimated steps measured by the GT3X® ActiGraph and Google Fit® respectively were 276.7 ± 97.6 and 481.0 ± 119.8; that calculated from the examiner's measurements was 472.0 ± 93.9. Statistically significant associations were found between the actual steps and those estimated by the GT3X® ActiGraph (r = 0.56; p