Leen Haerens

The contribution of preschool playground factors in explaining children's physical activity during recess

BackgroundLow levels of physical activity are characteristic in preschoolers. To effectively promote physical activity, it is necessary to understand factors that influence young childrens physical activity. The present study aimed to investigate how physical activity levels are influenced by environmental factors during recess in preschool.MethodsPreschool playground observations and pedometry during recess were carried out in 39 randomly selected preschools (415 boys and 368 girls; 5.3 ± 0.4 years old). In order to examine the contribution of playground variables to physical activity levels, taking adjustment for clustering of subjects within preschools into account, multilevel analyses were conducted.ResultsDuring recess boys took significantly more steps per minute than girls (65 ± 36 versus 54 ± 28 steps/min). In both genders higher step counts per minute were significantly associated with less children per m2 and with shorter recess times. Only in boys a hard playground surface was a borderline significant predictor for higher physical activity levels. In girls higher step counts were associated with the presence of less supervising teachers. Playground markings, access to toys, the number of playing or aiming equipment pieces and the presence of vegetation or height differences were not significant physical activity predictors in both genders.ConclusionIn preschool children physical activity during outdoor play is associated with modifiable playground factors. Further study is recommended to evaluate if the provision of more play space, the promotion of continued activity by supervisors and the modification of playground characteristics can increase physical activity levels in preschoolers.

The contribution of psychosocial and home environmental factors in explaining eating behaviours in adolescents

Objective:The present study aimed at investigating the influence of food availability, rules and television viewing habits on eating behaviours in adolescents.Design:Cross-sectional study.Setting:Four randomly selected middle schools.Subjects:A sample of 534 seventh and eighth graders.Interventions:Validated questionnaires were used to measure the family environment and fat, soft drink and fruit consumption. Hierarchical regression analyses on fat, soft drink and fruit consumption, with demographic and psychosocial variables entered as the first and environmental factors as the second block were conducted in boys and girls.Results:Boys with more unhealthy products available at home consumed more fat (P⩽0.001, 95% CI: 8.2–29.4) and more soft drinks (P⩽0.01, 95% CI: 0.2–1.4). Boys who reported better television viewing habits ate more fruit (P⩽0.001, 95% CI: −1.7 to −0.5). Girls who reported better television viewing habits consumed less fat (P⩽0.01, 95% CI: 1.4–9.0) and more fruit (P⩽0.05, 95% CI: −1.0 to −0.1). Girls who reported higher availability of healthy products at home (P⩽0.05, 95% CI: 0.3–3.1) and more food rules (P⩽0.001, 95% CI: −1.8 to −0.5), consumed more fruit. Environmental factors were poor predictors of soft drink consumption among girls.Conclusion:Availability of (un)healthy food products, family food rules and TV viewing habits were related to one or more eating behaviours in boys or girls. Although home environmental factors can play an important role in influencing adolescents’ eating behaviours, these factors were generally less predictive than demographic and psychosocial variables.Sponsorship:Ghent University and Policy Research Centre Sport, Physical Activity and Health funded by the Flemish Government.

Body Mass Effects of a Physical Activity and Healthy Food Intervention in Middle Schools

Objective: To evaluate the effects of a 2‐year middle school physical activity and healthy food intervention, including an environmental and computer‐tailored component on BMI and BMI z‐score in boys and girls.

Motivational Profiles for Secondary School Physical Education and Its Relationship to the Adoption of a Physically Active Lifestyle among University Students.

The promotion of an active lifestyle is one of the central aims of physical education (PE). The present study aimed at investigating the relation between students’ motivation for PE and activity levels using self-determination theory as a guiding framework. A retrospective design was used involving 2617 university students, of which 878 (33.5 percent) were male (age 20.6 1.9). Validated questionnaires were used to measure motivation for PE, self-reported concurrent (activity levels at secondary school) and delayed transfer (activity levels at university). A combination of hierarchical and non-hierarchical cluster analyses was used to generate motivational profiles for PE. Differences in activity levels were analysed using MANCOVAS. The results revealed that students with more optimal (i.e. more autonomous) motivational profiles reported more transfer and reported being more active at secondary school and in early adulthood. Implementing strategies that enhance self-determined motivation might result in more students’ adopting an active lifestyle.

The effects of a middle-school healthy eating intervention on adolescents' fat and fruit intake and soft drinks consumption

OBJECTIVES To evaluate the effects of a middle-school healthy eating promotion intervention combining environmental changes and computer-tailored feedback, with and without an explicit parent involvement component. DESIGN Clustered randomised controlled trial. SETTING Fifteen West-Flemish (Belgian) middle schools. SUBJECTS A random sample of 15 schools with 2991 pupils in 7th and 8th grades was randomly assigned to an intervention group with parental support (n = 5), an intervention group without parental support (n = 5) and a control group (n = 5). In these 15 schools an intervention combining environmental changes with computer-tailored feedback was implemented. Fat and fruit intake, water and soft drinks consumption were measured with food-frequency questionnaires in the total sample of children. RESULTS In girls, fat intake and percentage of energy from fat decreased significantly more in the intervention group with parental support, compared with the intervention alone group (all F>3.9, P < 0.05) and the control group (all F>16.7, P < 0.001). In boys, there were no significant decreases in fat intake (F = 1.4, not significant (NS)) or percentage of energy from fat (F = 0.7, NS) as a result of the intervention. No intervention effects were found in boys or in girls for fruit (F = 0.5, NS), soft drinks (F = 2.6, NS) and water consumption (F = 0.3, NS). CONCLUSIONS Combining physical and social environmental changes with computer-tailored feedback in girls and their parents can induce lower fat intake in middle-school girls. However, to have an impact on the consumption of soft drinks and water, governmental laws that restrict the at-school availability of low-nutritive products may be necessary.

Objectively measured sedentary time and physical activity time across the lifespan: a cross-sectional study in four age groups

BackgroundFrom a health perspective it is suggested to promote a positive balance between time spent in light intensity physical activity (LIPA) and sedentary behaviour (SB) (i.e. spending more time in LIPA than time spent in SB). However, no studies have reported prevalence rates of the LIPA-SB balance yet. The aim of this study was to objectively investigate the time spent in SB, in LIPA and moderate-to-vigorous intensity physical activity (MVPA) in four Belgian age groups and to explore which proportion of the population had a favorable balance between LIPA and SB and combined this with recommended amount of MVPA.MethodsAccelerometer data from 7 cross-sectional studies (N=2083) in four age groups (preschoolers, primary schoolchildren, secondary schoolchildren and adults) were aggregated. Differences in SB and PA between age groups and between men and women were determined by two-way MANCOVA. LIPA-SB balance was calculated and participants were categorized into one of four groups: (1) positive LIPA-SB balance (LIPA> SB) & sufficient MVPA (2) negative LIPA-SB balance & sufficient MVPA (3) positive LIPA-SB balance & insufficient MVPA (4) negative LIPA-SB balance & insufficient MVPA.ResultsFor the total sample, 55% of the waking time was spent in SB, 39% in LIPA and 6% in MVPA. Differences in SB between age groups was dependent from gender (p<0.001). Further, a positive LIPA-SB balance was assessed in 18% of the total sample and only 10% combined this positive balance with recommended amount of MVPA. Secondary schoolgirls were most at risk, with only 1% of the sample combining a positive LIPA-SB balance with sufficient MVPA. Another risk group was the large proportion (43%) of adult men who combined sufficient MVPA with a negative LIPA-SB balance.ConclusionA high proportion of the Belgian population is at risk if taking into account both SB and PA levels. Secondary schoolgirls have the unhealthiest SB and PA profile and are therefore an important target group for interventions both increasing MVPA and decreasing SB. In men more attention should be given in promoting a positive LIPA-SB balance independently from their compliance with the MVPA guidelines.

Explaining the effect of a 1-year intervention promoting physical activity in middle schools: a mediation analysis.

OBJECTIVE The aim of the present study was to examine the mediation effects of changes in psychosocial determinants of physical activity (attitude, social support, self-efficacy, perceived benefits and barriers) on changes in physical activity. DESIGN One-year intervention study with baseline and 1-year post measures of physical activity habits and psychosocial correlates. SETTING Fifteen middle schools. SUBJECTS Boys and girls (n = 2840) aged 11-15 years completed the validated questionnaires during class hours. RESULTS The product-of-coefficients test was used to asses the mediating effects. Self-efficacy for physical activity at school was found to be the only significant mediator of physical activity change. Specifically, self-efficacy for physical activity at school partly mediated the effect of the intervention on total and school-related physical activity change in the intervention group with parental support (P < 0.05). None of the other potential mediators, attitudes, social support, perceived benefits and perceived barriers, seemed to have had a positive effect. Even a suppressor effect was found for attitudes. Given that the effects of self-efficacy and attitudes were of opposite direction, the total mediated/suppressed effects of the intervention were not statistically significant. CONCLUSIONS Positive changes in total and school-related physical activity in adolescents could be partly explained by increases in self-efficacy for physical activity at school through a physical activity intervention in middle schools with parental support. However, the suppressor effect of attitudes decreased this effect. As this is one of the first true mediation analyses in this age group, further research is needed to replicate the importance of these mediators.

Using the intervention mapping protocol to develop a community-based intervention for the prevention of childhood obesity in a multi-centre European project: the IDEFICS intervention

BackgroundThe prevalence of childhood obesity has increased during the past decades and is now considered an urgent public health problem. Although stabilizing trends in obesity prevalence have been identified in parts of Europe, preventive efforts in children are still needed. Using the socio-ecological approach as the underlying theoretical perspective, the IDEFICS project aimed to develop, implement and evaluate a community-based intervention for the prevention of childhood obesity in eight European countries. The aim of the present manuscript was to describe the content and developmental process of the IDEFICS intervention.MethodsThe intervention mapping protocol (IMP) was used to develop the community-based intervention for the prevention of childhood obesity in 3 to 10 years old children. It is a theory- and evidence-based tool for the structured planning and development of health promotion programs that requires the completion of six different steps. These steps were elaborated by two coordinating centers and discussed with the other participating centers until agreement was reached. Focus group research was performed in all participating centers to provide an informed basis for intervention development.ResultsThe application of the IMP resulted in an overall intervention framework with ten intervention modules targeting environmental and personal factors through the family, the school and the community. The summary results of the focus group research were used to inform the development of the overall intervention. The cultural adaptation of the overall intervention was realised by using country specific focus group results. The need for cultural adaptation was considered during the entire process to improve program adoption and implementation. A plan was developed to evaluate program effectiveness and quality of implementation.ConclusionsThe IDEFICS project developed a community-based intervention for the prevention of childhood obesity by using to the intervention mapping heuristic. The IDEFICS intervention consists of a general and standardized intervention framework that allows for cultural adaptation to make the intervention feasible and to enhance deliverability in all participating countries. The present manuscript demonstrates that the development of an intervention is a long process that needs to be done systematically. Time, human resources and finances need to be planned beforehand to make interventions evidence-based and culturally relevant.

Evaluation of a Computer-Tailored Physical Activity Intervention in Adolescents in Six European Countries: The Activ-O-Meter in the HELENA Intervention Study

PURPOSE The present study investigates the effect of the Activ-O-Meter, an internet-based computer-tailored physical activity intervention in adolescents in six European centers involved in the HELENA study. METHODS Adolescents (12-17 years old) from Vienna, Ghent, Heraklion, Dortmund, Athens, and Stockholm were randomized into intervention and control schools. Participants in the intervention condition received the computer-tailored advice at baseline and after 1 month. Participants in the control condition received a generic standard advice. Effects were evaluated after 1 (n = 675) and 3 months (n = 494) using multi-level modeling. Physical activity levels were measured using the International Physical Activity Questionnaire for adolescents (IPAQ-A). RESULTS After 1 month, the intervention group reported higher levels of moderate (beta = -32.8, 95% CI (confidence interval): -64.2 to -1.4) and vigorous (beta = -28.0, 95% CI: -50.7 to -5.3) physical activity in leisure time, as well as higher levels of cycling for transport (beta = -19.1, 95% CI: -34.4 to -7.6) compared to the control group. After 3 months, when the intervention group had received the tailored feedback twice, intervention effects were even stronger. Favorable changes in physical activity levels of all intensities and in different contexts were found in the tailored group compared to the control group. Among adolescents not reaching the physical activity recommendations at baseline similar effects as in the total sample were found. CONCLUSIONS The data indicated that the computer-tailored physical activity intervention had positive effects on physical activity levels among the adolescents. However, the implementation of the computer-tailored intervention in the schools was not feasible in all countries.

Relationship of physical activity and dietary habits with body mass index in the transition from childhood to adolescence: a 4-year longitudinal study

OBJECTIVE To explore the relationship between several physical activity (PA) and dietary behaviours and BMI Z-score and to investigate the relationship between changes in these variables and in the BMI Z-score over a 4-year period from childhood to adolescence. DESIGN Longitudinal study in which children were included in the fifth grade and measured for four consecutive years. Dietary and PA behaviours as well as height and weight were measured by means of self-reported validated questionnaires. SETTING Fifty-nine Flemish elementary schools. SUBJECTS The baseline sample consisted of 51·9 % boys and the mean age was 10 (sd 0·4) years. During the first measurement year (2002), data on 1670 fifth graders were gathered. These measurements were repeated after 1 (n 1557), 2 (n 1151) and 3 (n 807) years. RESULTS Significant inverse relationships with BMI Z-score were observed for frequency of breakfast consumption (β = -0·033, se = 0·012) and frequency of sports participation (β = -0·011, se = 0·004) across four time points. Significant inverse relationships between changes in BMI Z-score and changes in frequency of sports participation (β = -0·011, se = 0·006) and hours of physical education (PE; β = -0·052, se = 0·023) were observed, meaning that decreases in sports participation and hours spent in PE were associated with increases in BMI Z-score. CONCLUSIONS The present study provides an important insight into different dietary and PA behaviours related to (changes in) BMI Z-score during the transition from childhood to adolescence.