Step-based metrics and overall physical activity in children with overweight or obesity: cross-sectional study

Background: Best-practice early interventions to increase physical activity (PA) in children with overweight and obesity should be both feasible and evidence based. Walking is a basic human movement pattern that is practical, cost-effective, and does not require complex movement skills. However, there is still a need to investigate how much walking—as a proportion of total PA level—is performed by children who are overweight and obese in order to determine its utility as a public health strategy. Objective: This study aimed to (1) investigate the proportion of overall PA indicators that are explained by step-based metrics and (2) study step accumulation patterns relative to achievement of public health recommendations in children who are overweight and obese. Methods: A total of 105 overweight and obese children (mean 10.1 years of age [SD 1.1]; 43 girls) wore hip-worn accelerometers for 7 days. PA volumes were derived using the daily average of counts per 15 seconds, categorized using standard cut points for light-moderate-vigorous PA (LMVPA) and moderate-to-vigorous PA (MVPA). Derived step-based metrics included volume (steps/day), time in cadence bands, and peak 1-minute, 30-minute, and 60-minute cadences. Results: Steps per day explained 66%, 40%, and 74% of variance for counts per 15 seconds, LMVPA, and MVPA, respectively. The variance explained was increased up to 80%, 92%, and 77% by including specific cadence bands and peak cadences. Children meeting the World Health Organization recommendation of 60 minutes per day of MVPA spent less time at zero cadence and more time in cadence bands representing sporadic movement to brisk walking (ie, 20-119 steps/min) than their less-active peers. Conclusions: Step-based metrics, including steps per day and various cadence-based metrics, seem to capture a large proportion of PA for children who are overweight and obese. Given the availability of pedometers, step-based metrics could be useful in discriminating between those children who do or do not achieve MVPA recommendations.This study was conducted under the umbrella of the ActiveBrains and the SmarterMove projects supported by the MINECO (Ministerio de Economía y Competitividad)/FEDER (Fondo Europeo de Desarrollo Regional) (DEP2013-47540, DEP2016-79512-R, and RYC-2011-09011). JHM and JMG are supported by grants from the Spanish Ministry of Education, Culture and Sport (FPU15/02645 and FPU14/06837). CCS is supported by a grant from the Spanish Ministry of Economy and Competitiveness (BES-2014-068829). PMG is supported by a grant from the European Union’s Horizon 2020 research and innovation program (No. 667302). This study has been partially funded by the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES), and by the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades, and European Regional Development Fund (ERDF) (reference SOMM17/6107/UGR and reference RD16/0022). In addition, funding was provided by the SAMID III (red de SAlud Materno Infantil y Desarrollo) network, RETICS (REdes Temáticas de Investigación Cooperativa en Salud), funded by the PN (Plan Nacional) I+D+I (Investigación + Desarrollo + Innovación) 2017-2021 (Spain), ISCIII (Instituto de Salud Carlos III)–Sub-Directorate General for Research Assessment and Promotion and the EXERNET Research Network on Exercise and Health in Special Populations (DEP2005-00046/ACTI), and the European Union’s 2020 research and innovation program under grant agreement No. 667302. Likewise, this research was supported, in part, by the Intramural Research Program at the National Institute on Aging, USA