This study provides new evidence adding to the existing literature on correlates of pedometer-based physical activity in children. We found that the achievement of pedometer-based cut-points  was associated with the child's own behavior (i.e., active transport to school, screen-based activity), the physical activity levels of their peers, and the characteristics of their neighborhood (i.e., school neighborhood-SES, proximity of a friend's house, the presence of local destinations).
Girls were more likely to achieve the suggested pedometer-based cut-points. Consistent with previous evidence [27–29, 33] boys accumulated more daily steps than girls, yet they were less likely than girls to achieve this level of pedometer-based physical activity. Duncan et al.  found a similar pattern among 8-11 year old boys and girls. This discordance likely reflects the higher pedometer-based cut-point for boys (≥15000 steps/day) compared with girls (≥12000 steps). Only nineteen percent of boys and 32% of girls achieved the pedometer-based cut-point - somewhat lower than the prevalence for elementary school-aged children (grade 3, 5, and 7) found in a recent Western Australian survey (boys = 31.7% and girls = 43.9%) . However, the studies differed in a number of ways, including the specific grades captured, the sample design, the season in which data were collected, as well as the method for collecting and recording pedometer data (i.e., steps recorded daily vs. steps recorded after seven-days from the in-built memory). Nevertheless, our results correspond more closely with recent Australian national data suggesting that 24% of boys and 33% of girls ages 9-13 achieved these same pedometer-based cut-points . We found no association between school grade and achievement of the pedometer-based cut-points, consistent with studies that have found no relationship between steps and age among children [22, 39].
Previous research has shown positive associations between maternal education, family income and physical activity levels among adolescents however, the relationship between SES and physical activity among children is less clear . We found no association between household SES--parent education and home ownership--and achievement of the pedometer-based cut-points. Children attending a school in a higher socioeconomic neighborhood were more likely to achieve the pedometer-based cut-points compared with those attending schools in low socioeconomic neighborhoods, even after accounting for household indicators of SES. Disadvantaged neighborhoods often offer fewer physical activity opportunities for children . While our walkability index captured pedestrian connectivity and traffic exposure, it is possible that other environmental characteristics related to neighborhood SES exist (e.g., land-use mix, aesthetics, and safety).
Level of independent mobility, such as going to local shops, school, friends, or park unsupervised, may be associated with increased outdoor play, participation in structured sport and exercise, and walking and cycling to and from school [41, 42]. As well as potentially decreasing physical activity opportunities, restricting independent mobility may negatively influence a child's cognitive and social development by reducing opportunities to socialize and explore and interact with their neighborhood environment [43, 44]. Moreover, children with restricted mobility may spend more time participating in passive modes of transportation, particularly for travel to school . Although children who were not allowed to play in their neighborhood unsupervised were less likely to achieve the pedometer-based cut-points, this was not statistically significant. Nevertheless, we did find that children who were usually driven to or from school were less likely to achieve the pedometer-based cut-point, suggesting that active transportation such as walking can contribute to overall levels of physical activity. Positive associations between levels of active transportation and physical activity, including pedometer-based physical activity among youth have been reported elsewhere [46, 47]. Creating safe child-friendly neighborhoods, changing parent and child perceptions and attitudes towards motor vehicle use, encouraging parents to walk or be active in their neighborhoods with their children, and implementing sustainable walk to school programs could encourage independent mobility and active transportation which may contribute to increasing levels of physical activity.
There has been a recent focus on the independent contribution of sedentary behavior on the health of both adults and children [48, 49]. We found that children who spent more than two hours daily on screen-based activity took fewer steps and were less likely to achieve the pedometer-based cut-points. Our finding is important as only modest or null associations between time spent in screen-based activity and steps among children have been previously found [49–51]. Interventions that decrease screen-based activity could contribute to higher levels of physical activity participation among children.
School neighborhood walkability and parent perceptions of traffic barriers and safety or neighborhood friendliness were not associated with pedometer-based physical activity. We did find, however, a negative relationship between the count of different neighborhood destinations that parents perceive to be within a 10-minute walk of home and achieving the pedometer-based cut-points. Some destinations captured in this study might be considered less important for encouraging children to be more physically active (e.g., libraries and news agencies). The presence of more local destinations might also result in the neighborhood being less supportive of physical activity among children of this age because of more destination-related motor vehicle traffic, limited area for play spaces and the presence of more strangers visiting local neighborhoods. An alternative explanation is that fewer steps are needed to travel to destinations that are closer to home. Nevertheless, Frank et al. , for example, found objectively-assessed mix of land uses to be positively associated with walking among adolescents but not children aged 5-11 years. Furthermore, others have noted negative associations between environmental characteristics usually supportive of physical activity among adults (i.e., street connectivity) and walking in children . The lack of association between the perceived neighborhood environment and pedometer-based physical activity is not surprising as evidence of this relationship among pre-adolescent children is mixed .
Children whose friend's house was within a 10-minute walk were more likely to achieve pedometer-based cut-points. Children with friends residing nearby might visit more frequently using active modes, may be involved in active play, and may have company to walk to and from school. Together this may result in more walking and physical activity. There is evidence for associations between friend support and physical activity among children . In support, we also found a positive association between a child's pedometer-based physical activity and the physical activity level of their peers (within the same grade level at their school) - with the association slightly stronger for boys than girls. Peer physical activity levels might encourage physical activity behaviors among youth . Our finding could reflect peer modeling or support, or unmeasured influences of the school (i.e., quantity and quality of physical education or school sports) or the neighborhood environment on physical activity. In addition, boys were less likely to achieve the pedometer-based cut-point if they resided further than a 10-minute walk of their nearest relative's home, whereas girls were more likely to achieve the cut-point. Speculatively, girls might be more willing to walk further than boys to visit relatives resulting in higher recorded pedometer-based physical activity. More research is needed to disentangle these associations.
Several limitations should be considered when interpreting the findings of this study. Differences between the analytical sample and the excluded participants were observed. In particular the analytical sample was more physically active, thus the results presented might underestimate the magnitude of the associations between the correlates and pedometer-based physical activity. Moreover, the moderate reliability of some variables may have attenuated the estimated associations between these correlates and the outcome. The generalizability of these results are limited to school-aged children in grades 5-7 attending elementary schools in high and low walkable neighborhoods determined based on pedestrian connectivity and traffic exposure. Other objectively-assessed environmental characteristics not measured here could be important for determining pedometer steps among children, although more research is needed to identify these characteristics. We examined the correlates of one set of recently suggested pedometer-based physical activity cut-points , thus the associations found here may not generalize to other existing pedometer-based cut-points for children and adolescents. Children and adolescents achieving the pedometer-based cut-points used in this study may be less likely to be classified as overweight and obese compared with those not achieving these cut-points  however, we did not examine the association between steps and weight status or any other health outcome. Future research should investigate the extent to which achievement of the various established pedometer-based physical activity cut-points result in positive health outcomes including, but not limited to, improved weight status among children and adolescents. Finally, associations found from this cross-sectional study cannot be considered causal.