Comparison of Sedentary Estimates between activPAL and Hip- and Wrist-Worn ActiGraph

Purpose: Sedentary behavior is an emerging independent health risk factor. The accuracy of measuring sedentary time using accelerometers may depend on the wear location. This study in older adults evaluated the accuracy of various hip-and wrist-worn ActiGraph accelerometer cutoff points to define sedentary time using the activPAL as the reference method. Methods: Data from 62 adults (mean age, 78.4 yr) of the Aging Research Evaluating Accelerometry study were used. Participants simultaneously wore an activPAL accelerometer on the thigh and ActiGraph accelerometers on the hip, dominant, and nondominant wrist for 7 d in a free-living environment. Using the activPAL as the reference criteria, we compared classification of sedentary time to hip-worn and wrist-worn ActiGraph accelerometers over a range of cutoff points for both 60-s and 15-s epochs. Results: The optimal cutoff point for the hip vertical axis was