Comparing Participants' Rating and Compendium Coding to Estimate Physical Activity Intensities

Abstract

This study assessed agreement between participants' rating (PMET) and compendium coding (CMET) of estimating physical activity intensity in a population of older minority women. As part of the Women on the Move study, 224 women completed a 7-day activity diary and wore an accelerometer for 7 days. All activities recorded were coded using PMET and CMET methodologies. MET-mins were computed for total activity in 10 activity dimensions (MET = metabolic equivalent, where 1 MET is the amount of energy expended at rest). Results revealed that correlations between the two methods were high (ranging from .81 to .98) but the means were significantly different (p < .05) for total activity and for 7 of the 10 activity dimensions. In general, MET-mins based on PMET were higher than those based on CMET, and agreement between methods was low (ranging from .26 to .31). Revising the MET values assigned to PMET improved agreement with CMET. Accelerometer MET-mins were significantly associated with total activity for both methods; however, their correlations were low. Agreement with accelerometer MET-mins was low and was similar for revised PMET and CMET. The revised participants' rating provides an alternative method to rank individuals because it provides similar results to the compendium coding; however, neither method accurately estimates accelerometer MET-mins.