Objective: The aim of the present study was to explore the existence of clusters in multiple lifestyle behaviours, including physical activity (PA), sedentariness and food habits, in young adolescents. The present study also investigated whether the identified groups could be characterised by gender and components of health-related physical fitness, especially weight status and cardiorespiratory fitness (CRF). Design: A cross-sectional survey. Leisure-time PA, sedentary behaviour and food consumption were assessed by a questionnaire. Overweight prevalence was estimated using BMI (kg/m 2 ) calculated from self-reported height and weight. CRF was measured using a 20 m shuttle-run test. Setting: The study was conducted in four middle schools in Flanders, Belgium. Subjects: The sample size was 317 seventh grade students aged 11-12 years. Results: Four reliable and meaningful lifestyle clusters could be identified, labelled as 'Sporty media-oriented mixed eaters' (boys: n 34; girls: n 16), 'Academic healthy eaters' (boys: n 30; girls: n 58), 'Inactive healthy eaters' (boys: n 38; girls: n 57) and 'Inactive media-oriented unhealthy eaters' (boys: n 35; girls: n 49). The lifestyle clusters could not be characterised by adolescents' weight status. Among boys, the 'Sporty media-oriented mixed eaters' group performed significantly better on the shuttle-run test than those in clusters with the lowest levels of PA (clusters 3 and 4). Conclusions: Our results showed that healthy and risk-related behaviours may coexist in some groups of young adolescents. Isolated unhealthy behaviours, such as high levels of screen-based media use or high consumption of energydense food items, are not necessarily related with negative health outcomes, on the condition that these risk-related behaviours co-occur with more healthenhancing behaviours such as PA. Dramatic increases in childhood obesity over the past decades suggest the predominance of influential behavioural factors over genetic factors. It is generally believed that today's environment enforces an inactive lifestyle that is likely to contribute to a positive energy balance and childhood obesity (1) . Despite the important role of nutrition (energy input) and physical activity (PA; energy output) in the prevention of childhood obesity, there seems to be limited research addressing the relationship between multiple health behaviours or clusters based on this energy-balance approach (2)(3)(4) . Previous literature in this area has mainly focused on describing bivariate associations between PA and sedentary behaviour (5) , PA and food choices (6,7) or sedentary behaviour and food choices (8,9) . Although significant relationships may exist between two health behaviours, the reported correlations are predominantly weak and often too small to be of much clinical or practical significance. Nevertheless, the low correlations between health-related behaviours does not exclude the existence of clusters or groups of young people who show negative health profiles due to factors such...

Based on the self-determination theory, this study investigated the mediating role of the satisfaction of the three psychological needs (need for competence, relatedness and autonomy) in the relation between need support from the physical education (PE) teacher and autonomous motivation to engage in PE and between the physical school environment and autonomous motivation to engage in PE. Data were collected from 2418 6th grade children. Analyses were performed using bootstrapping. The results showed that perceptions of competence and autonomy mediated the relation between need support from the PE teacher and autonomous motivation. Moreover, the perception of autonomy also mediated the relation between the physical school environment and autonomous motivation. These findings suggest that not only the PE teacher but also the physical school environment is able to promote autonomous motivation by satisfying the need for autonomy.

Objectives: The present study tested a motivational sequence in which children's goals for leisure-time sport and physical activity (PA) from Goal Content Theory predicted pedometerdetermined PA through behavioural regulation constructs from Self-Determination Theory. Design:Quantitative cross-sectional study.Method: A sample of 1,272 Flemish (Dutch speaking part of Belgium) sixth graders (M age = 11.42 years) filled in a questionnaire on PA goal content, behavioural regulations and pubertal status. Children's height and weight were measured to assess Body Mass Index (BMI). To measure daily PA behaviour, participants wore a pedometer for seven consecutive days.Structural equation modelling was performed to test the proposed motivational sequence and to examine the mediation effect of behavioural regulations towards leisure-time sport and PA on the relation between PA goal content and daily step counts.Results: A structural equation model supported the hypothesized sequence in which intrinsic goals for leisure-time sport and PA predicted children's daily step counts through autonomous motivation towards leisure-time sport and PA. Multi-sample invariance testing revealed that the proposed model was largely invariant across BMI groups, pubertal status and gender. Conclusion:The findings highlight the importance of emphasizing intrinsic goals for participation in leisure-time sport and PA in children aged 10-12 years. By stimulating children to participate in PA and sports by referring to intrinsic goals, children are more likely to enjoy PA, which in turn might increase the likelihood of a regular and long-term PA engagement.

No longitudinal change in pedometer-determined PA was observed. Nevertheless, the decline in self-reported moderate-to-vigorous PA suggests that the transition to secondary school induced a change in the contribution of different types of PA. Finally, time spent on homework and recreational computer use increased during the school transition.

Based on Self-Determination Theory (Deci & Ryan, 2000), this study tested whether changes in autonomous motivation toward physical education (AMPE) during the transition from elementary to secondary school can be predicted by changes in perceived need support from the physical education (PE) teacher and perceived physical school environment. Self-reported data were gathered from 472 Flemish (northern part of Belgium) students in 6th grade (2009) and again in 8th grade (2011). Mediation analyses showed that an increase in perceived need support from the PE teacher was related to an increase in AMPE (boys: β = .42; girls: β = .50). In boys, this relation was mediated by changes in perceived competence (β = .08). In girls, this relation was mediated by changes in perceived autonomy (β = .12), perceived competence (β = .14), and perceived relatedness (β = .05). This study shows that PE teachers should be need-supportive to maintain a good quality of motivation in students.

Children's PA/SB and the supportive role of parents at age 11 to 12 are strong predictors of PA and screen-based SB at age 13 to 14.

Based on self-determination theory, the purpose of this study was to explore the mediating role of autonomous motivation in the relation between environmental factors and pedometer-determined PA among 10- to 12-year-old Flemish children. Data were collected from 787 6th grade pupils and one of their parents. Children completed self-report measures including autonomous motivation for PA and perceived autonomy support for PA by parents and friends. Parents completed a questionnaire concerning their PA related parenting practices (logistic support and explicit modeling) and the perceived home environment with respect to PA opportunities. The results confirmed that autonomous motivation mediated the relation between children’s PA and their perceived autonomy support by friends and parents. Autonomous motivation also mediated the relation between parental logistic support and PA. In addition, a positive direct relation was found between parental explicit modeling and children’s PA, and between perceived neighborhood safety and children’s PA.

These results suggest there are differences in the ambulatory physical activity patterns of children in the UK and Belgium.