Objectives: To determine if subpopulations of students benefit equally from school-based physical activity interventions in terms of cardiorespiratory fitness and physical activity. To examine if physical activity intensity mediates improvements in cardiorespiratory fitness.Design: Pooled analysis of individual participant data from controlled trials that assessed the impact of school-based physical activity interventions on cardiorespiratory fitness and device-measured physical activity.Participants: Data for 6621 children and adolescents aged 4–18 years from 20 trials were included.Main outcome measures: Peak oxygen consumption (VO_2PeakmL/kg/min) and minutes of moderate and vigorous physical activity.Results: Interventions modestly improved students’ cardiorespiratory fitness by 0.47 mL/kg/min (95% CI 0.33 to 0.61), but the effects were not distributed equally across subpopulations. Girls and older students benefited less than boys and younger students, respectively. Students with lower levels of initial fitness, and those with higher levels of baseline physical activity benefitted more than those who were initially fitter and less active, respectively. Interventions had a modest positive effect on physical activity with approximately one additional minute per day of both moderate and vigorous physical activity. Changes in vigorous, but not moderate intensity, physical activity explained a small amount (~5%) of the intervention effect on cardiorespiratory fitness.Conclusions: Future interventions should include targeted strategies to address the needs of girls and older students. Interventions may also be improved by promoting more vigorous intensity physical activity. Interventions could mitigate declining youth cardiorespiratory fitness, increase physical activity and promote cardiovascular health if they can be delivered equitably and their effects sustained at the population level.

Background: Understanding parental barriers is crucial to promote active commuting to school since the parental perceptions influence how young people commute. This study examined parental barriers to active commuting to school among Spanish children and adolescents, and their association with their gender and the usual mode of commuting. Methods: Parents of children (n = 628) and parents of adolescents (n = 151) from Granada (Spain) completed a paper-based questionnaire about perceived parental barriers to active commuting to school and mode of commuting. Data were analyzed using the Chi-square test. Results: Among Spanish parents, the most common barriers reported by parents of children were traffic volume and dangerous intersections, whereas the most frequent barriers reported by parents of adolescents were distance to school and dangerous intersections. Compared to parents of children, a greater proportion of parents of adolescents reported distance to school and crime and smaller proportion reported traffic volume as barriers to active commuting to school. Among parents of children, crime was a more commonly reported as a barrier by parents of girls. Although some barriers reported by parents of passive commuters were similar for children and adolescents (such as distance to school and absence of a policeman at crosswalks), other barriers were specific to parents of children. Conclusions: The main parental barriers to active commuting in children were traffic volume and dangerous intersections whereas for adolescents were distance and dangerous intersections. Among Spanish parents, parental barriers to active commuting are influenced by children’s age, gender and mode of commuting to school.

The main objectives of this study were: to compare the barriers to active commuting to and from school (ACS) between children and their parents separately for children and adolescents; and to analyze the association between ACS and the children’s and parents’ barriers. A total of 401 child–parent pairs, from Granada, Jaén, Toledo and Valencia, self-reported, separately, their mode of commuting to school and work, respectively, and the children’s barriers to ACS. T-tests and chi-square tests were used to analyze the differences by age for continuous and categorical variables, respectively. Binary logistic regressions were performed to study the association between ACS barriers of children and parents and ACS. Both children and adolescents perceived higher physical and motivational barriers and social support barriers towards ACS than their parents (all p < 0.05). Additionally, the parents perceived higher distance, traffic safety, convenience, built environment, crime-related safety and weather as barriers towards ACS, than their children (all p < 0.05). Moreover, a higher perception of barriers was related to lower ACS. The results of our study showed the necessity of attenuating the perceptions of children and their parents in order to increase ACS. This is relevant to develop interventions in the specific contexts of each barrier and involving both populations.

The lack of physical activity and increasing time spent in sedentary behaviours during childhood place importance on developing low cost, easy-toimplement school-based interventions to increase physical activity among children. The PREVIENE Project will evaluate the effectiveness of five innovative, simple, and feasible interventions (active commuting to/from school, active Physical Education lessons, active school recess, sleep health promotion, and an integrated program incorporating all 4 interventions) to improve physical activity, fitness, anthropometry, sleep health, academic achievement, and health-related quality of life in primary school children. A total of 300 children (grade 3; 8-9 years of age) from six schools in Granada (Spain) will be enrolled in one of the 8-week interventions (one intervention per school; 50 children per school) or a control group (no intervention school; 50 children). Outcomes will include physical activity (measured by accelerometry), physical fitness (assessed using the ALPHA fitness battery), and anthropometry (height, weight and waist circumference). Furthermore, they will include sleep health (measured by accelerometers, a sleep diary, and sleep health questionnaires), academic achievement (grades from the official school’s records), and health-related quality of life (child and parental questionnaires). To assess the effectiveness of the different interventions on objectively measured PA and the other outcomes, the generalized linear model will be used. The PREVIENE Project will provide the information about the effectiveness and implementation of different school-based interventions for physical activity promotion in primary school children.