The preschool years (defined as between 3 and 5 yr) are foundational in the development of health behaviors, such as physical activity and engagement in screen-based entertainment (8,24). Participation in these behaviors has been linked with health and social outcomes in young children, including weight status (26), timing of adiposity rebound (26), blood pressure (29), cardiorespiratory fitness and serum cholesterol (12), bone mineral content and density (17), behavioral problems (21), educational attainment in adulthood (13), reading (40) and social competence (20). It is important, therefore, to determine how much time preschool children spend being physically active and engaged in screen-based entertainment.
Although results across previous studies clearly show boys participate in more physical activity than girls do (15), few have used objective measures of physical activity, and differences in results from objective measures may be evident. Further, although previous studies have generally reported no differences in television viewing between boys and girls (16), possible differences in total screen time (television/video/DVD viewing, computer/Internet, and electronic game use) between the sexes remain unexamined. In addition, age appears to be unrelated to both physical activity and television viewing (15,16); however, it may be associated with increased time in other screen-based entertainment such as electronic game and computer use (3).
Recent reviews of physical activity prevalence in preschool children (23,37) generally show that only a small proportion of time is spent being active, and many children fail to meet physical activity recommendations (37). Many of those studies have used the National Association for Sport and Physical Education (NASPE) guidelines of ≥1 h of structured and ≥1 h of unstructured physical activity every day (2). However, those guidelines do not prescribe intensity of physical activity, and use of the terms “structured” and “unstructured” has led to different interpretations across studies, making comparisons difficult. As a result, reports of adherence to the recommended amount of physical activity in preschool children vary substantially. For example, some studies report that a large proportion of preschool children achieve sufficient physical activity to meet those guidelines (22,25); however, other studies have reported that preschool children largely fail to achieve sufficient physical activity (18,27,28). Differences in methods of measuring physical activity may also contribute to varying estimates of compliance with recommendations because proxy-report methods show higher levels of compliance than do objective measures. Although there is no known evidence that suggests preschool children must participate in moderate-to-vigorous physical activity to gain health benefits, the majority of studies that have investigated adherence to the NASPE guidelines have focused on moderate-to-vigorous physical activity and have rarely reported total physical activity (light-to-vigorous).
Studies of screen-based entertainment in preschool children have tended to focus on television viewing as the behavior of interest and have compared time spent watching television with the American Academy of Pediatrics (AAP) recommendations that stipulate no more than 2 h·d−1 for children 2 yr or older (1). Reports on prevalence of preschool children achieving the recommended amount of television viewing suggest that between 34% (35) and 80% (19) of children watched television and/or videos/DVDs for <2 h·d−1. The lack of inclusion of time in other screen-based behaviors may potentially underestimate total time spent in screen-based entertainment.
The Australian Government’s Department of Health and Ageing recommendations for physical activity and screen-based entertainment for children younger than 5 yr were released in October 2009 (11). Those recommendations propose that preschool children (3–5 yr) achieve a minimum of 3 h of physical activity every day, spread throughout the day, and engage in no more than 1 h of screen-based entertainment a day. The Australian recommendations propose children participate in physical activity of any intensity—light, moderate, or vigorous—and the cumulative total contributes toward achieving the recommended amount. In addition, the recommendations include participation in all screen-based activities (i.e., television, video and DVD viewing, computer and Internet use, and other electronic game use) as contributing toward the total time children spend in screen-based entertainment. To date, there are no data available on the percentage of preschool children who meet the Australian recommendations for physical activity or screen-based entertainment.
This study aimed to 1) identify the percent of time a sample of Australian preschool children spend being physically active, 2) investigate how much time preschool children spend in screen-based behaviors, 3) investigate differences in physical activity and screen-based behaviors by sex and age, and 4) determine the prevalence of adherence to published recommendations for physical activity and screen-based entertainment in preschool children.
Recruitment and Participants
The data are drawn from the Healthy Active Preschool Years study, a cohort study established to investigate correlates of physical activity and sedentary behavior and to track changes in those behaviors in young children over time. Preschools and childcare centers located in low, medium, and high socioeconomic position (SEP) areas of metropolitan Melbourne, Australia, were targeted through a two-stage stratified random sampling process. In the first stage, all Melbourne metropolitan local government areas (LGAs; n = 29) were divided into quintiles, based on the 2001 Socio-Economic Indices for Areas Index of socioeconomic advantage and disadvantage (4). Two LGAs from each of the lowest, middle, and highest quintiles were randomly selected. Each selected LGA was contacted and granted permission for the researchers to contact local preschools and childcare centers. Preschools (preschools provide education to children before the commencement of compulsory school education; sometimes called kindergartens) and childcare centers (childcare centers provide long day care to children aged from 6 wk to school-age; sometimes called nursery or long day care) were identified from each LGA and then randomly ordered separately within each LGA.
In the second stage of sampling, the first 16 childcare centers and the first 16 preschools (referred to collectively as “centers”) were selected in each of the two low-SEP LGAs. In the four LGAs in the middle and highest SEP areas, the first 10 childcare centers and the first 10 preschools were selected from each. Participants from low SEP areas are often underrepresented in research, so in this study, low SEP areas were oversampled (30,36). If a center declined to participate, the next center on the respective LGA list was approached. Recruitment and data collection occurred in two phases: 1) July to November 2008 and 2) May to October 2009. In total, 156 childcare centers and 137 preschools were approached. The final sample consisted of 71 (46%) childcare centers and 65 (47%) preschools. Reasons for center nonparticipation included the following: currently undergoing accreditation, staff too busy, too many non–English-speaking parents, already participated in several research projects, not enough time, and not interested in participating in research.
After approval from the director/head teacher/manager of each center, all parents of children aged 3 yr or older were invited to participate via written information letters and consent forms, distributed directly into the children’s individual files/pockets at each center or directly to parents by the center staff. Reminders were distributed 1–2 wk after the initial information letters. Ethical approval was provided by the Deakin University Human Research Ethics Committee and the Victorian Department of Education and Early Childhood Development.
Measures and Data Management
Parents completed a survey that sought information on demographic details, the time the child usually spent in screen-based behaviors (TV/video/DVD viewing, electronic games, and computer use) during a typical week, and the child’s usual sleep time (test–retest reliability: intraclass correlation = 0.72, 95% CI = 0.58–0.86). Parents reported the total amount of time their child spent in each of the screen-based behaviors during the week (Monday to Friday) and on weekends (Saturday and Sunday). Total time spent in each behavior across the week was calculated by summing weekday and weekend day minutes. Weekly totals for all behaviors were summed to determine the total time the child spent in screen-based entertainment across the week. Test–retest reliability of total weekly screen-based entertainment was acceptable (intraclass correlation = 0.68, 95% CI = 0.52–0.83), and this total was divided by seven to determine the average daily time each child spent in screen-based entertainment. Child’s date of birth was used to determine child’s age at the time of measurement, and parents reported the sex of their child. Data from surveys were entered by a commercial data entry company and then transposed into SPSS version 17.0 (32) for cleaning and amendments where necessary.
Children were fitted with an ActiGraph model GT1M accelerometer (Pensacola, FL) on an elasticized belt. ActiGraph 7164 accelerometers are the only accelerometers that have established utility, validity, and reliability in children age 3–5 yr (10), and the GT1M model has superseded the 7164. Children and parents (via written information) were instructed that the accelerometer was to be worn on the right side of the hip from waking for the entire day, removed only for sleeping and aquatic activities (swimming and bathing). Data were collected in 15-s epochs to maximize opportunities to more accurately capture the sporadic nature of young children’s physical activity (10,31). Children wore accelerometers for an 8-d period, including the day of fitting and removal; however, because of some monitors not being returned on time, actual wear time for some children was up to 10 d. Each monitor was initialized to commence recording at 9:00 a.m. on the day of fitting, and data management adjusted for actual wear time. Data were downloaded after return of the monitor, and raw data files were then managed by a specially developed series of macros in Excel (Microsoft Corp., Redmond, WA), followed by specially developed code in Stata (College Station, TX). Physical activity was operationalized as light–moderate–vigorous activity in accordance with recent studies (5,7,38) and the Australian recommendations (11).
Parent survey and accelerometer data files were merged, by matching unique case identification numbers, and analyzed within Stata Version 11 (34). For each child, the usual daily wake time was determined from parent-reported usual sleep time. Parent-reported sleep time included nighttime sleep and daytime nap if appropriate. Wake time was calculated by subtracting total sleep time (night and day) from 1440 min (24 h).
Average movement counts per minute (cpm) were derived from the data, and percentage of time worn in light-, moderate-, and vigorous-intensity activities were determined individually for each day, and across the entire wear period, using age-specific cut points (31) (3 yr: <301, <614, <1230, ≥1231; 4 yr: <363, <811, <1234, ≥1235; 5 yr: <398, <890, <1254, ≥1255; sedentary and light-, moderate-, and vigorous-intensity activities, respectively; counts per 15-s epoch). Light-, moderate-, and vigorous-intensity activities were combined to determine total physical activity. The amount of time a child spent being physically active was determined by multiplying the child’s usual waking hours by the percent of time the child spent in total physical activity; that is, (wake time) × (percent of time in total physical activity) = (no. of minutes in total physical activity).
A participant was included in the study if he or she had a minimum of three weekdays and one weekend day of accelerometry data, with data for at least 50% of his or her usual wake time on each day. Spearman–Brown analysis indicated that up to 2.5 weekdays and up to 1.4 weekend days were required to achieve reliability of 0.8 for weekdays and weekend days, respectively, which is generally accepted as sufficient to determine reliability (33). Accelerometry data were then weighted to represent a standard week comprised of five weekdays and two weekend days.
Descriptive statistics were used to present characteristics of the sample. Because the physical activity outcome variable was a proportion (proportion of time being physically active) and bounded by 0 and 1, the standard assumptions of linear regression were not met. Therefore, generalized linear modeling, using a binomial family and logit transformation (14), was used to determine whether associations existed between age and proportion of time in total physical activity, between sexes for proportion of time being sedentary and in each intensity of physical activity, and between sexes for adherence to recommendations. Generalized linear modeling with a Gaussian distribution and identity link was used to test for between-sex and age differences in screen-based entertainment. All analyses controlled for clustering by center of recruitment.
Adherence to the physical activity recommendations was calculated in two ways. First, the average time per day children spent being active across the entire wear period was compared with the recommendations (average method). Second, the time each child spent in physical activity on each valid day of accelerometry data was compared with the recommendations (every day method). As the total number of valid days of accelerometry data varied between children, the percent of valid days on which each child met the recommended amount of physical activity was calculated. Adherence to the screen-based entertainment recommendations was calculated as the average time per day each child spent in those behaviors because individual-day data were not available.
Data were collected from 1004 children and their parents. In total, 943 parents completed surveys, of whom 93.7% were female respondents. Respondent parents had an average age of 37.3 yr (95% CI = 36.9–37.6), and 69.8% were born in Australia. Children (n = 939) had a mean age of 4.5 yr (95% CI = 4.5–4.6). There were slightly more boys (54.0%) than girls in the final sample. The final sample included 703 children who met the criteria for valid accelerometry data and 935 children who had valid data for total weekly screen-based entertainment.
Children who met the criteria for inclusion (minimum of three weekdays and one weekend days) wore the accelerometers for an average of 647.5 min·d−1 (95% CI = 642.8–652.3) across an average of 6.9 days (95% CI = 6.8–7.0). Table 1 shows results for counts per minute and percent of time in intensity of activity for the total sample and by sex. Overall, children spent 16.4% (95% CI = 16.1–16.7) of their time in total physical activity. Across an average day, children in the study participated in a mean of 127.2 min (95% CI = 124.8–129.6) of total physical activity. Boys recorded significantly more counts per minute and a greater percentage of time in light, moderate, and total physical activity than girls did (P < 0.001 for all). There was no difference between boys and girls in percentage of time spent in vigorous-intensity physical activity. Age was inversely associated with physical activity such that boys and girls spent 12% less time being active with each additional year of age (odds ratio = 0.88, 95% CI = 0.84–0.92 for both).
Almost all children watched television (99.4%). Approximately one-third (31.1%) of children played computer or other traditional electronic games and 28.8% used a computer/Internet for something other than games. Table 2 presents the results for the amount of time children spent in each of the screen-based behaviors and in total screen-based entertainment. Overall, children spent an average of 112.5 min (95% CI = 107.8–117.2) in screen-based entertainment per day. Boys (n = 504) and girls (n = 431) spent an average of 114.8 min·d−1 (95% CI = 108.3–121.3) and 109.7 min·d−1 (95% CI = 102.9–116.5), respectively, in screen-based entertainment. Time spent in screen-based entertainment did not differ between boys and girls. Older children spent an average of 9 min more in screen-based entertainment per day for each additional year of age (odds ratio = 1.09, 95% CI = 1.01–1.16).
Adherence to recommended levels of physical activity and screen-based entertainment
Table 3 shows the percentage of children who achieved 2 and 3 h of total physical activity for the total sample and by sex. Overall, 5.1% of the children in this study achieved the Australian recommendation (11) of ≥3 h of physical activity (6.7% of boys and 3.2% of girls, P = 0.068) on an average day. Just more than half (56.3%; 63.9% of boys and 49.8% of girls, P < 0.001) the children achieved the NASPE guidelines (2) of 2 h of physical activity across a day.
Table 3 also shows the percentage of children who achieved each of the Australian- and AAP-recommended amounts of screen-based entertainment. Overall, 21.8% of children (21.6% of boys and 22.0% of girls, P = 0.934) met the Australian screen-based entertainment recommendation of ≤1 h·d−1. A considerably larger percentage of children achieved the AAP recommendation of ≤2 h·d−1 (58.9%; 56.9% of boys and 61.3% of girls, P = 0.193). Only 0.8% of children met both the Australian physical activity and screen-based entertainment recommendations. Almost one-third of children (32.3%) achieved both the NASPE and AAP recommendations.
Table 4 shows the percentage of children who achieved the Australian and NASPE recommended level of physical activity and the percent of valid days on which they achieved the recommended amount. More than half the children (55.2%) in the sample failed to meet the Australian recommendation on any days of monitoring and none achieved the Australian recommended amount of physical activity on every day of monitoring. By contrast, only 9.4% of children failed to achieve the NASPE-recommended amount of physical activity on even one day, and 11.5% of children achieved the recommended amount on every day. Boys achieved significantly more days meeting both the Australian (P < 0.001) and NASPE (P < 0.02) recommendations than did girls.
Only three studies (5,7,38) have previously reported accelerometer-assessed physical activity compliance with the NASPE guidelines, and none has reported on compliance with the Australian recommendations. Those studies included 419 children in the United States (5), 245 children in Portugal (38), and 76 children in Belgium (7). Therefore, there have been no studies using accelerometry data to estimate the proportion of Australian preschool children achieving sufficient physical activity, and other studies have used relatively small samples. Estimates of adherence to the NASPE guidelines from previous studies vary between 0% and 99.9%, depending on the cut points used, the interpretation of the guidelines as total or moderate–vigorous physical activity, and the amount of time (60 or 120 min·d−1) spent being active (5). However, when the guidelines are interpreted as in this study, that is, 120 min of total physical activity, differences in adherence vary depending on the cut points applied to the accelerometry data. Nonetheless, when using the same cut points, previous studies have found much lower rates of compliance than the current study. For instance, Cardon and De Bourdeaudhuij (7) found that 27% of children in Belgium achieved the NASPE recommended amount of physical activity, and Beets et al. (5) found that 13.5% of girls and 17.5% of boys in the United States met the guidelines. Differences in compliance rates are confusing in light of similar findings in both previous studies and the current study for percent of time, or minutes per day, spent in physical activity: 15.3% (7) and 127 min·d−1 (5), respectively, compared with 16.5% and 127 min·d−1 in the current study. However, both those studies used smaller samples, and that, combined with other potential differences in methodologies and environments, may well account for the reported differences in findings.
Most preschool children in the Healthy Active Preschool Years study spent only a small proportion of their time being active and also participated in high levels of screen-based entertainment. Boys and younger children were more active than girls and older children, respectively, and although no differences were evident between the sexes for time spent in screen-based entertainment, older children spent significantly more time in screen-based entertainment than younger children. Adherence to the Australian recommendations was low for both physical activity and screen-based entertainment, with virtually none of the children surveyed meeting both recommendations. Children in the sample fared substantially better against the NASPE and AAP recommendations, with almost one-third of children meeting both those recommendations. Nonetheless, the majority of children failed to meet both recommendations.
Clearly, the Australian recommendations are more stringent than those from NASPE and AAP. Although the evidence base on which the Australian recommendations were developed is yet to be published, the recommended amounts of physical activity (which includes light, not just moderate-to-vigorous, physical activity) and screen-based entertainment were agreed to through a consensus process. That process involved advice from leading experts in physical activity, sedentary behavior, obesity, and child health and broad stakeholder consultations with a range of individuals, health and medical practitioners, and government and nongovernment organizations. It is likely that studies such as this will add to the evidence base for the Australian recommendations, which may well evolve over time.
As the Australian recommendations for physical activity and screen-based entertainment were only released in October 2009, this is the first study to report adherence to these recommendations. Only one previous study has reported the prevalence of children accruing 3 h of physical activity across a day (22). That study used parent report of preschool children’s active play time as their measure of physical activity and found that 55% and 79% of children achieved 3 h of active play on weekdays and weekend days, respectively (22). It is likely that differences between findings in the previous and current studies are largely attributable to different measurement methodologies. Overall, inadequate data exist on the prevalence of recommended levels of physical activity in preschool children. The data that exist suggest that many children are not participating in adequate amounts of physical activity.
Several studies have reported preschool children’s participation in screen-based entertainment; however, those studies have generally focused on television/DVD/video viewing and have neglected other screen-based behaviors. Previous findings have shown that preschool children watch an average of between 2.1 and 3.2 h of television per day (6,22) and, in some cases, as much as 5.6 h·d−1 (35). The present study found that children engaged in an average of 1.9 h of screen-based entertainment per day, slightly lower than findings from previous studies, particularly considering the inclusion of screen-based entertainment other than television viewing. Estimates of adherence with the AAP recommendations vary widely. For example, Vandewater et al. (39) reported that 56% of 3- to 4-yr-olds and 70% of 5- to 6-yr-olds met the AAP guideline of ≤2 h of television/DVD/video viewing. Kuepper-Nybelen et al. (19) found that between 53% and 93% of children in their study watched <2 h of television per day. Okely et al. (22) reported that 70% and 73% of children met the AAP recommendations on weekend days and weekdays, respectively.
Research commonly finds that preschool boys are more active than their female counterparts (15) and that association was also found in this study. Further, this study found that significantly more boys than girls achieved the NASPE recommendations for physical activity, which has only been examined and reported in one previous study (38). Conversely, sex has frequently been found to not be associated with television viewing and other screen-based behaviors (16), and this study supports this finding. This suggests that girls may need additional support to achieve optimal levels of physical activity and sex-specific intervention strategies may be warranted. However, as many boys also recorded low levels of physical activity, promoting physical activity participation to all preschool children is necessary. In addition, strategies to decrease preschool children’s time in screen-based entertainment should be directed at all children regardless of sex.
Although age has previously been shown to have no association with physical activity (15), this study found an inverse association between physical activity and age. This finding may be partly attributable to the age-specific cut points, which increase with age, used to interpret the accelerometry data (31). Nonetheless, this finding is concerning as preschool children spend only a small percentage of their time being active. Decreases from such a low base at an early age indicate that preschool children need to be supported to obtain optimal levels of physical activity so that, when their participation does decline, they are still active enough to achieve health benefits. Further, interventions should aim to stem declines in physical activity, particularly during the early years of a child’s life. Findings for the association between television viewing and age have been inconsistent across studies (16). This study found that older children spent significantly more time in screen-based entertainment, although that difference was minimal at only nine additional minutes per day for each additional year of age. However, as most children exceeded the screen-based entertainment recommendation, it would be prudent to encourage parents and other caregivers to minimize time in those behaviors as much as possible and to provide them with skills and strategies to achieve this aim.
Strengths and limitations of the current study must also be acknowledged. The sample used in this study is not representative of all preschool children, particularly those in rural or regional areas or those who do not attend preschool or childcare. Nonetheless, a strength of this study is the large, heterogeneous sample used and the use of an objective measure of physical activity, whereas previous studies have tended to use much smaller samples and subjective measures of physical activity. Much contention exists about which accelerometer cut points are most appropriate to use with accelerometry data, and previous studies (5) have clearly shown that substantial differences in estimates of physical activity prevalence and compliance with recommendations exist when using different cut points. Age-specific cut points published by Sirard et al. (31) have been used in this study as they are commonly used in the literature and therefore allow for comparison between studies. Limitations also exist around the use of the parental proxy report of screen-based entertainment for preschool children because parents may not accurately report their child’s screen-based entertainment time. In addition, parents only reported the time their child spent in screen-based entertainment at home, and other recent studies suggest that children may spend up to twice as much time in television viewing across a day when use at preschool/childcare is considered (9,35). Including time in screen-based entertainment during care hours in the estimate of children’s daily screen-based entertainment would have strengthened this study, however, those data were not available for this sample. However, the current study included a range of screen-based entertainment options that have rarely been included in previous studies, showed acceptable reliability, and provided a more comprehensive representation of screen-based entertainment in this population. Recruitment in low-SEP areas resulted in lower response rates per center than in mid- and high-SEP areas (data not reported), and it is possible that some families did not consent to participate because of the need to complete a survey if their written English was not strong. Parent report of child’s “usual daily sleep time” may have been slightly less accurate for those children who spent greater amounts of time away from their parents and a daily report of “actual” rather than “usual” sleep time may have been slightly more accurate. Nonetheless, this item (data not reported) and total daily sleep time showed good reliability.
The findings from this study suggest that preschool children are insufficiently active and engage in excessive amounts of screen-based entertainment. Interventions to support participation in healthful levels of physical activity and screen-based entertainment are required for the preschool population. It would be prudent for staff and teachers at preschools and childcare centers to remove any screen-based entertainment activities from their daily programs, as it is clear from this research that preschool children already engage in an excessive amount of those behaviors in their home environments.
In summary, preschool children spend very little time being active but a substantial amount of time engaged in screen-based entertainment. Relatively few children met the Australian physical activity or screen-based entertainment recommendations, and virtually no children met both. Although substantially more children met both the NASPE and AAP recommendations, most children still failed to comply. Developing a comprehensive understanding of the underlying factors influencing preschool children’s physical activity and screen-based entertainment behaviors is imperative to supporting healthful behaviors during the important preschool period. Further research is required to identify modifiable correlates of physical activity and screen-based entertainment that may be used to better inform and target future interventions in preschool, and younger, children.
T.H. was supported by a Deakin University A.P.A. Ph.D. Scholarship during the first half of data collection. J.S. is supported by a National Heart Foundation of Australia Career Development Award and sanofi-aventis. K.H. is supported by a National Heart Foundation of Australia Career Development Award. D.C. is supported by a Victorian Health Promotion Foundation Senior Research Fellowship.
The project was funded by Deakin University.
The authors declare no conflict of interest.
The results of the present study do not constitute endorsement by the American College of Sports Medicine.
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