Validity of Step Counting Methods over One Day in a Free-Living Environment

This thesis was designed in two parts to determine the step count accuracy of activity monitors in a free-living environment. The aims of the first and second part of the study were to (1) critically evaluate the effects on step counts using the study methodology of wearing multiple monitors on the same area of the body and to (2) determine the step count accuracy of numerous consumer- and research-grade activity monitors worn on various locations of the body across all hours of a day in a free-living environment, respectively. For both parts of the study, the same hip- and wrist-worn monitor brands were examined. Wrist monitors included the ActiGraph GT9X (GT9X), Fitbit Alta (FA), Garmin Vivofit 3 (GV), and Apple Watch Series 2 (ApW). Hip monitors included the ActiGraph GT9X (GT9X), Fitbit Zip (FZ), Omron HJ-325 (OM), Yamax Digiwalker SW-200 (YX). In the second part of the study, a thigh-worn monitor, activPAL (AP), was also examined.