An evaluation of energy expenditure estimation by three activity monitors.

A comparative evaluation of the ability of activity monitors to predict energy expenditure (EE) is necessary to aid in the investigation of the effect of EE on health. The purpose of this study was to validate and compare the RT3, the SWA and the IDEEA at measuring EE in adults and children. Twenty-six adults and 22 children completed a resting metabolic rate (RMR) test and performed four treadmill activities at 3 km.h(-1), 6 km.h(-1), 6 km.h(-1) at a 10% incline, 9 km.h(-1). EE was assessed throughout the protocol by the RT3, the SWA and the IDEEA. Indirect calorimetry (IC) was used as a criterion measure of EE against which each monitor was compared. Mean bias was assessed by subtracting EE from IC from EE from each monitor for each activity. Limit of agreement plots were used to assess the agreement between each monitor and IC. Limits of agreement for resting EE were narrowest for the RT3 for adults and children. Although the IDEEA displayed the smallest mean bias between measures at 3 km.h(-1), 6 km.h(-1) and 9 km.h(-1) in adults and children, the SWA agreed closest with IC at 6 km.h(-1), 6 km.h(-1) at a 10% incline and 9 km.h(-1). Limits of agreement were closest for the SWA at 9 km.h(-1) in adults representing 42% of the overall mean EE. Although the RT3 provided the best estimate of resting EE in adults and children, the SWA provided the most accurate estimate of EE across a range of physical activity intensities.