Highlighting this phenomenon, an analysis of PubMed citations by date on the use of the Fitbit WPAM alone revealed that during the period from January 1, 2012, to December 31, 2013, there were 8 publications; between January 1, 2014, and December 1, 2014, there were 53 publications; and between January 1, 2016, and June 20, 2017, there were 135 publications.
Wearable physical activity monitors (WPAMs) provide opportunities to advance the assessment and promotion of PA, and there has been a proliferation of these devices within the past 8 years, with >400 wearable monitors currently in the market today, sold by over 250 different companies (2).
Terminology is important to clarify when it comes to the use of the words "wearable physical activity monitors" as other phrases exist, such as "exercise tracker," "activity tracker," "fitness tracker," "step tracker," "consumer activity tracker," and "activity or exercise monitor." There is also a distinction between research-grade WPAMs and commercial or consumer-WPAMs.
Other published works (8) have reviewed the full extent of how research-grade WPAMs work, which extends to the technology of consumer-WPAM devices.
Other review articles have provided in-depth explanations of inferences drawn from PA engagement (9).In brief, WPAMs measure movement, and this movement unit is typically recorded as a step or an acceleration signal, for instance, a count or a g per second (g referring to the force of acceleration due to gravity at the Earth's surface).
Consumer-WPAMs tend not to be equivalent to one another or to research-grade WPAMs for estimations of energy expenditure or time spent in MVPA (16), and thus they are generally not suitable as measurement tools for precise estimates of energy expenditure.
The supreme court agreed with the WPAM
statement, "The income approach may be the most useful method for valuing subsidized housing." It stated that the income approach is superior when applied to subsidized housing "due to the conditions of the agreement and the limited availability of data." The WPAM
recognizes dissimilarities between subsidized properties and market-rate properties.