Measuring physical activity of elementary school children with unsealed pedometers: Compliance, reliability, and reactivity.

Background and Purpose: Evidence of compliance, reliability, and reactivity of using pedometers in children remains inconsistent. This study aimed to examine these aspects of unsealed pedometers. Methods: There were 133 children who wore pedometers for 7 days. A subsample of 50 children completed surveys measuring self-efficacy, enjoyment, parental influence, and environment on Day 1 and 8. Investigator presence and incentives were used to increase compliance. Results: About 87% of children returned pedometers, with 62% wearing pedometers for 4 days or longer. The intraclass correlation coefficients ranged from .70 to .87, with ICC for 4-day pedometer steps exceeding .80. Wearing pedometers did not change pedometer steps nor alter children's perceptions of self-efficacy, enjoyment, parental influence, and environment significantly. Conclusions: Children were compliant wearing pedometers, and there was no reactivity from wearing them.Keywords: measurement; physical activity; pedometer; child; psychometricsLack of consistent physical activity is a significant contributor to the current childhood obesity epidemic in the United States (Hills, Andersen, & Byrne, 2011). Obesity rates are disproportionately higher among children aged 6-11 years old compared to preschoolers aged 2-5 years old or adolescents aged 12-18 years old (Ogden & Carroll, 2010). For children who participate in afterschool programs, their prevalence (39%) of overweight or obesity is higher than the national average of 32% (Trost, Rosenkranz, & Dzewaltowski, 2008) and their physical activity levels decreased from 2004 to 2008 (Arundell et al., 2013). Considering the key role of physical activity in preventing and controlling childhood obesity, accurate measurement of physical activity is paramount for both observational and interventional studies. Various instruments have been developed to assess physical activity among children. Pedometers are the most widely used devices because they are relatively inexpensive ($10-$50; McClain & Tudor-Locke, 2009), user-friendly (Clemes & Biddle, 2013), objective (Clemes & Biddle, 2013), reliable (Rowe, Mahar, Raedeke, & Lore, 2004), and valid (McNamara, Hudson, & Taylor, 2010).Although significant strides and accomplishments in rigorous research have been made to address the psychometric properties and feasibility of using pedometers, other issues such as compliance of wearing and returning pedometers, the number of weekday and/ or weekend days of data needed, and behavioral and psychosocial reactivity of wearing pedometers still exist and need further clarification, especially in children. Previous research with U.S. children reported the compliance of wearing pedometers ranging from 46% to 98%, with most studies reporting a compliance of 60% (Drenowatz et al., 2010; Eisenmann, Laurson, Wickel, Gentile, & Walsh, 2007; Strycker, Duncan, Chaumeton, Duncan, & Toobert, 2007). However, no study has been identified to investigate the strategies to increase children's compliance of wearing and returning pedometers.Because children's physical activity habits may vary from day to day because of weather, school attendance, and participation in sports or physical education, there is no consistent evidence on how many days and which days (weekday vs. weekend) are needed to reliably and adequately estimate children's physical activity without producing avoidable participation burden (Clemes & Biddle, 2013). Few studies have investigated the number of days needed to obtain a reliable estimate of children's physical activity. One study of 11,669 children aged 5-19 years old suggests that 2 days is sufficient to determine average daily steps of children (Craig, Tudor-Locke, Cragg, & Cameron, 2010). Some researchers, however, suggest using 7 consecutive days or at least 1 weekday and 1 weekend day (Clemes & Biddle, 2013), whereas others recommend 4 full days with at least 1 weekend day (Dollman et al. …