Children's segment specific light physical activity across two years of school- based program

IntroductionFor a long time, being sufficiently physically active was considered the opposite of having a sedentary lifestyle (Verloigne et al., 2012). Despite, high levels of physical activity are not necessarily equal to low levels of sedentary time, given that children meeting the moderate to vigorous physical activity (MVPA) guidelines (U.S. Department of Health and Human Services, 2008; World Health Organization, 2010) can still be sedentary for many hours per day (Biddle et al., 2004; Owen et al., 2000). Making sure that children do not sit down for long periods of time can help them perform better in school and to improve their health (European Community's Seventh Framework Programme, 2012; Trembley et al., 2014). Many school-based interventions which attempted to increase children's MVPA, focused on adding greater periods of time in active play, sports or other physically active behaviors within school hours (Carrell et al., 2005; Jamner et al., 2004; Simon et al., 2004; Ward, 2011). Less priority has been given to daily light physical activity (LPA), although all activities carried out in a non-sitting posture are of great value to children's well-being and health (European Community's Seventh Framework Programme, 2012; Physical Activity as Civil Skill Program, 2010-2014). Light physical activities, such as walking to school or friends, playing active games, getting the mail, or housework may reduce the thresholds to engage the greater physical activity levels, since school-aged children, for instance, in Australia, Canada, Columbia, Finland, South-Africa, the U.S. (Trembley et al., 2014) and Asian countries (Muller, Khoo & Lambert, 2013) do not engage in sufficient physical activity. Therefore, it is essential to investigate children's LPA with greater scrutiny to improve the future school-based interventions for children and youth.LPA is defined as any activities with intensity between sedentary behavior and moderate-intensity physical activity, and it involves lower energy expenditure than MVPA, but higher energy expenditure than inactivity (Kwon et al., 2011). The decreasing levels of physical activity are partly due to insufficient participation in leisure time activities. Likewise, an increase in the use of passive modes of transport has also been associated with declining physical activity levels (World Health Organization, 2015). The benefits of MVPA on children's well-being and health is mainly explained by energy expenditure associated with physical activities (World Health Organization, 2012; 2015). However, the importance and levels of light-intensity activities are largely unknown (Grasten et al., 2014; Trembley et al., 2014). Recently, the global matrix of grades comparing children's physical activity levels in 15 countries from Europe, North-America, Africa, and Oceania showed that only a limited number of studies have been carried out in order to examine LPA related activities (Trembley et al., 2014). In fact, only five countries informed that they have enough data to grade "active play" indicator, whereas ten countries graded "active play" indicator as incomplete because of insufficient data or lack of clarity on the benchmark or the definition of active play (Trembley et al., 2014). For instance, data from New Zealand indicated that approximately 75% of children reported participating in active play (Maddison et al., 2010) spending on average 78 minutes per day in free play (Zealand SN, 2012). In contrast, the Finland Adolescent Health and Lifestyle Survey found that only 34% of 12to 18-year-olds participated in physical activities outside school or sports clubs at least four times per week (Adolescent health and lifestyle survey, 2013). The Australian Lifestyle of Our Kids study showed that children's LPA decreased from age of 11 to 12 years based on the accelerometer scores (Telford et al., 2013). Goran and Reynolds (2005) reported that 9 to 11-years-old boys' LPA decreased, when girls' LPA increased across an eight-week multimedia intervention to increase physical activity implemented in the States. …