This is an excerpt from Advanced Fitness Assessment and Exercise Prescription 8th Edition With Online Video by Ann Gibson,Dale Wagner & Vivian Heyward.
Being able to track energy (caloric) expenditure is of great importance for those pursuing weight loss and weight maintenance goals. But the technology to track energy expenditure (EE) with a high degree of accuracy is still lacking. Research results are mixed on the ability of activity trackers to accurately compute TEE in controlled laboratory settings, during semi-structured activities, and in free-living environments. Although the correlation between activity tracking accelerometers is reported to be moderate to strong, significant underestimations of the reference values are common. Accelerometers, categorized as research-grade (ActiGraph GT3X+, BodyMedia Core, Body Media SenseWear), underestimate energy expenditure in comparison to the gold standard, indirect calorimetry (Bai et al. 2016; Ferguson et al. 2015; Imboden et al. 2017; Kim and Welk 2015).
Consumer-targeted devices worn during a variety of activities produce large differences and variable estimates of EE and tend to underestimate reference values of EE (Bai et al 2016; Ferguson et al. 2015; Imboden et al. 2017; Kim and Welk 2015; Price et al. 2017; Sasaki et al. 2015). Typically, the proprietary algorithms developed by the manufacturers account for differences between devices. Although some accelerometers perform better during moderate- to fast-paced activities (ActiGraph GT3X+, BodyMedia SenseWear, Core Armband), others perform better during slow-paced activities (activPAL). Lyden and associates (2017) reported that the activPAL accurately categorizes sedentary behaviors as well as light-intensity and MVPA exercise compared with direct observation. Triaxial and multisensory devices tend to provide more accurate estimates of TEE than uniaxial devices (Van Remoortel et al. 2012).