Background
Time spent outdoors has consistently been associated with higher physical activity levels, [
1‐
7] and in a recent position statement, put forward by Tremblay and colleagues, [
8] active outdoor play in the natural environment was recognised as a fundamental component of children’s health and development. Not only is there more space for children to be physically active outdoors, [
9] but access to sedentary pursuits is also minimised because activities such as TV viewing and playing computer games are usually performed indoors. [
7] It is, therefore, not surprising that children engage in significantly more physical activity outside the home rather than when they are indoors [
9‐
11].
Despite the benefits of outdoor play, research suggests that children have less freedom to play outside than they did in previous generations [
8,
12,
13]. Many parents and grandparents cite that children no longer play traditional games or know how to ride a bike, both of which were frequent pastimes in their own childhood [
14]. According to qualitative data, [
15,
16] previously reported barriers to outdoor play have included safety concerns, a lack of time, and greater pressure on academic study, as well as access to digital entertainment in the home. However, there is little support in the literature for an association between safety perceptions and children’s physical activity, [
5,
12,
17,
18] and a negative, but weak, relationship was observed between screen-based behaviours and physical activity in a meta-analysis [
19]. The authors concluded that the effect is therefore unlikely to be clinically relevant [
19].
A key criticism of past work is that general measures of overall physical activity tend to be assessed, [
4,
17] as opposed to certain types of physical activity performed during specific times [
20]. In terms of the extant literature on time spent outdoors specifically, which is positively associated with physical activity, [
2,
3,
21] overall measures of this behaviour have also been explored (e.g., [
22‐
24]). Though it may be that screen-based pursuits are more likely to compete for children’s time outdoors after school or on weekends, when access to media-based entertainment is likely to be more prominent [
4]. This notion is supported by two Australian studies; one found that the majority (78%) of time after school was spent indoors among 5–7 year olds, [
9] while the other reported that this period contributed to 84% of children’s daily screen time among a larger sample of 8–9 year olds. [
25] Furthermore, different aspects of parental perceptions of safety, such as traffic- and crime-related concerns, are rarely considered separately. [
18] Thus, important relationships may have been missed in previous research because associations may differ between the two.
Consequently, the purpose of this study was to explore the relationships between indoor sedentary pursuits (specifically TV viewing, recreational computer use, and access to home electronic media devices), and parental perceived crime- and traffic-related safety concerns, with outdoor time after school and over the weekend. Given potential differences between boys and girls and socioeconomic groups, highlighted in past research, [
6,
26] we also tested for interactions with sex and socioeconomic status (SES).
Discussion
The aim of this study was to extend previous research on children’s physical activity, by exploring potential correlates of time spent outdoors, a consistent correlate of children’s physical activity, [
3] during specific periods when children have more free choice over their behaviour. The results provide new insight into the relationships between parental safety concerns, screen-based behaviours, and time spent outdoors after school and on weekends. Group differences were also found, as well as interactions by sex and SES.
Boys and low SES children were more likely to spend > 1 h outside after school than girls and high SES participants, respectively. These relationships did not hold for time spent outside on weekends, but older children were more likely to spend > 2 h outdoors during this time, although this relationship was only significant among girls and high SES participants. These results are interesting as they align with previous research on independent mobility showing that boys, [
16,
28,
40‐
43] children of a low SES background, [
42‐
45] and older children, [
16,
42,
43,
45] tend to be given greater freedom to roam. As such, independent mobility may be an underlying mechanism that was at play in our study, but more research is needed to confirm this, since independent mobility was not assessed here.
In terms of research on time outdoors specifically, our results concur with past work showing that boys tend to spend more time outdoors than girls [
6,
23,
28,
31]. As for socioeconomic differences, a negative relationship between parental education and time outdoors was reported among 3–4 year olds in the United States (US), [
24] and among children aged 7–12 years in the Netherlands, but no association was found for 4–6 year olds within the same study [
22]. No significant difference was reported in another US study on pre-schoolers aged 2–5 years, [
23] thus conflicting results have previously been reported. Age differences, other sample characteristics, and variations in the way that time spent outdoors is assessed, could explain these discrepancies. Research on UK children, exploring socioeconomic disparities in time spent outdoors is needed to support our findings. Future work would also do well to explore the reasons for any such divide between socioeconomic groups because they could point to differences in social norms, availability of technologies, or the built environment, which would help to improve future intervention design aimed at particular groups. For example, parents from different socioeconomic backgrounds may have different attitudes towards allowing their children to play outside, and this in turn may be influenced by whether there are spaces considered to be safe for outdoor play, such as a garden or a quiet cul-de-sac.
According to previous research, a weak negative relationship between sedentary behaviour and physical activity exists, [
19,
46] yet little is known about the relationship between screen-based behaviours and outdoor time specifically. Our findings suggest that the time spent playing on a computer is more important than the time watching TV, because a negative association was observed for computer use and outdoor time after school, whereas no overall effect for TV viewing was found. However, there were differences between the ‘extreme’ groups in that participants who watched a low amount of TV (< 2 h/day) on school days were less likely to spend > 1 h outside after school than those watching a high amount of TV (≥ 3 h/day).
In addition, access to a TV or non-handheld video game player in the bedroom was associated with higher odds of time outdoors after school in comparison to children without these. Similar findings were reported in a study of 7 year old children; the presence of a TV in the bedroom was positively associated with physical activity [
47]. The authors speculated that this may have been a marker of SES, as they also found low SES participants to be more active than their high SES counterparts [
47]. Yet, no significant interaction by SES was found for any of the sedentary pursuits explored in this study, so other factors could be at play. For example, children with access to very few electronic media devices or who watch very little TV, may live in households where screen time is more carefully monitored and/or highly prohibited. It is therefore possible that other rules and restrictions may be enforced, such as not being allowed to play outdoors unsupervised. Indeed, previous research has shown that greater restrictions on sedentary behaviours are negatively associated with physical activity [
48,
49]. Further research is needed to test whether this mechanism is feasible or whether other reasons, such as reverse causality, [
48] for these counter-intuitive findings are at play.
Nevertheless, our findings raise questions about the potential efficacy of previous strategies, such as the removal of devices from the bedroom or TV limiting devices, [
50,
51] that are proposed to increase children’s physical activity levels. However, such proposals are based on results showing that greater access to media devices in the child’s bedroom is negatively associated with children’s physical activity and positively with sedentary time, [
44,
49] which contrasts with our findings. Such differences may simply be due to the fact that we assessed outdoor time specifically, as opposed to overall physical activity, and it is possible that the children with access to more electronic devices in our study, may have spent more time outdoors inactive (e.g., engaging in social sedentary behaviours). Thus they may not necessarily be more active despite spending more time outside. Alternatively, there may be variations in the way that electronic media devices are reported (i.e., via child versus parent reports), [
52] and devices in the child’s bedroom may have contrasting effects to those that are portable in nature. As children have access to a number of sedentary screen-based devices, [
38] new research exploring the impact of time spent in other screen-based pursuits (e.g., tablet computers and smart phones) is needed as it will be important to know whether they add to, or replace, the use of existing devices already present in the home.
In terms of parental safety perceptions, a significant negative association was evident for traffic-related concerns and time outdoors after school among boys. This contrasts with the results of another UK study, whereby a negative relationship between traffic safety concerns and time spent outside was apparent among girls only [
53]. It is unknown why such a relationship was not observed for girls in this study, but it could be because fewer girls spent several hours outside during this time than boys. Furthermore, in contrast to our approach, in their study the authors examined outdoor time across the whole week as well as children’s perceptions of safety as opposed to parental perceptions [
53]. Again, such discrepancy in design may explain differences when compared to the present work. Nonetheless, it may be that road safety strategies targeting boys’ safe play or active transport around the neighbourhood may be needed among those who have parents that restrict their outdoor time. Though, safety measures should be enforced such that they do not compromise on children’s ability to partake in unsupervised outdoor play [
8,
54].
As for crime-related concerns, the results were less intuitive because higher concerns of this kind were associated with increased odds of time outside after school in this sample. It is possible that parents with more concerns experience these because their children spend more time outdoors, thus they may be more aware of potential dangers [
55]. Equally, it may be that such parents do not restrict their child’s behaviour despite feeling concerned. They may therefore have effective coping strategies; if so qualitative studies which look to explore these would be useful as they may provide a means for overcoming concerns among parents who do restrict their child’s outdoor time. On the other hand, it may be that these children spend more time outdoors in protest to any restrictions placed upon them, [
56] though this seems unlikely given the age group being studied. A more plausible explanation is that parents who report greater concerns may simply supervise their children’s outdoor play or active travel [
56]. This emphasises the importance of taking the whole context into account, by specifying where and with whom such behaviour takes place, as well as the need for longitudinal research given that the direction of this relationship is unknown because of the cross-sectional study design.
Limitations
This study is also limited by the use of self-reported measures to assess all variables included in the analysis and the questions used to measure time spent outdoors in particular were developed by the ISCOLE team, thus they have not been assessed for validity or reliability [
27]. It has been proposed that mixed methods designs, including both objective and subjective measures of outdoor play, and a standardized measurement tool should be employed in future research [
57]. Furthermore, our measure of time spent outdoors does not provide any information on the actual behaviours undertaken outdoors (e.g., walking, skating, playing, sitting etc.), nor did we capture information on where such behaviour took place (e.g., on the streets, in the school playground, in the garden etc.). Future work should take these factors into consideration as they may point to possible explanations for some of the group differences and counterintuitive findings reported in this study. However, a strength of this work is the inclusion of time-specific data for both screen-based pursuits and time spent outdoors, which can help to improve the predictive capacity of the relationships being tested [
58].
It is possible that other factors not studied here may play an important role (e.g., access to facilities, parent support, seasonality etc.) that should also be explored in future. Further, the majority of the sample classified themselves as White British (87.9%), and data were not collected on children living in rural areas. Consequently, the findings of this study may not generalise to other populations and important differences between ethnic groups or between urban and rural settings could not be assessed. Parental perceptions of the neighbourhood environment are more likely to be influential in this age group, though future studies should explore the impact of both children’s and parent’s perceptions, as they may have independent and/or interacting effects [
12,
53].
Acknowledgements
The authors are grateful to the participants along with their parents, teachers and headteachers for their involvement in the study. We thank Lydia Emm, PhD; Julia Zakrzewski, PhD; Clemens Drenowatz, PhD; and Oliver Perkins for their role in data collection for the UK site of ISCOLE. Additionally, we would like to thank the ISCOLE Coordinating Center staff at the Pennington Biomedical Research Center for study coordination and data management (Peter T. Katzmarzyk PhD and Timothy S. Church MD, principal investigators, and Denise Lambert, project manager). We would also like to recognize the principal investigators from the 12 participating countries who played a role in developing the research study design and protocol. Lastly, we are also appreciative to the contributions of the External Advisory Board for the ISCOLE project which includes Alan Batterham, PhD, Teesside University, Jacqueline Kerr, PhD, University of California, San Diego; Michael Pratt, MD, Centers for Disease Control and Prevention, Angelo Pietrobelli, MD, Verona University Medical School.