Date of Award

2016

Publisher

North Dakota State University

Document Type

Thesis

Degree Awarded

Master of Science (MS)

Department

Health, Nutrition and Exercise Sciences

College

Human Sciences and Education

Faculty Advisor

Byun, Wonwoo

Description

This study investigated the concurrent validity of two accelerometer-based physical activity (PA) monitors, the wrist-worn Fitbit Flex, and ActiGraph’s hip-worn GT3X+. Specifically, we examined the relationship, differences, and level of agreement between Fitbit and GT3X+ sedentary behavior (SED) and moderate-to-vigorous PA (MVPA) estimates. Sixty-seven adults (mean age: 47.1 ± 14.1, female: 73.1%) from North Dakota State University wore the Fitbit and GT3X+, and logged any sleep and non-wear time, for seven consecutive days in free-living conditions. GT3X+ estimates were calculated using ActiGraph Freedson, Troiano, and Freedson’s VM3 cut-points. Fitbit estimates were calculated via Fitabase. Only data during waking hours where both PA monitors were worn were analyzed. Fitbit and GTX+ estimates strongly correlated. Fitbit produced similar SED (mean difference = -35.83 minutes (min)/day), but significantly higher MVPA (mean differences = -59.7 – 77.41 min/day) to GT3X+. As the mean volume of MVPA increased, so did differences between Fitbit and GT3X+ estimates.

Rights

NDSU Policy 190.6.2

Rights Link

https://www.ndsu.edu/fileadmin/policy/190.pdf

Handle Identifier

https://hdl.handle.net/10365/28048

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