Comparison of Two ActiGraph Accelerometers in Laboratory and Free-Living Conditions

Objective: Evaluate the agreement between the GT3X+ and GT9X Link with respect to the vertical axis under laboratory and free-living conditions using the Normal Filter and LFE Filter, respectively and to evaluate the agreement between the minutes spent in different activity intensities between the devices under free-living conditions using both the Normal and LFE Filter, respectively. Methods: Eight participants (mean age = 28.3 ± 3.8) were enrolled. Participants completed 4 walking trials of 2 different speeds (2 and 3 miles per hour, 3-min stages) while wearing 2 GT3X+ and 2 GT9X Link accelerometers on an elastic belt on the right sides of the hip. They continued wearing them for another 6-10 hours in the free-living setting. Results: There were no significant differences between the mean CPM between the devices for the walking trials and free-living assessment when both filters were applied. There were also no significant differences in the different physical activity intensity categories. There was strong evidence of agreement between the GT3X+ and GT9X Link. Conclusion: Data collected with the GT3X+ and GT9X Link should be comparable across past and future studies.