Coordinated project whose objectives are: a) to assess the effectiveness of a physical activity intervention (MOVI-KIDS) on preventing obesity and improving fitness during the adiposity rebound period; and b) to examine the effectiveness of MOVI-KIDS on reducing the carotid intima-media thickness.

The prevalence of overweight in Spanish children in the puberty age is among the highest in the world and increasing quickly. Our group has done so far two interventions based on after-school programs of recreational physical activity to control obesity and other cardiovascular risk factors in primary school children (8-to-11 years)in Cuenca, Spain.

The first edition, called MOVI, showed moderate effect in reducing adiposity and improving the lipid profile, but did not significantly improve overall cardiometabolic risk, mainly because of did not reduce blood insulin levels. A second edition (MOVI-2), increased duration and intensity of the sessions and was more focused on increased muscle strength. Preliminary analysis also show a decrease in body fat, a reduction of global cardiometabolic because of decreased insulin levels.

Our project integrates a multidimensional intervention to promote physical activity, with a mixed design (cross-over randomized trial, and a qualitative study) and consist of two sub-projects that share the same study population: "Effectiveness of an intervention of physical activity promotion in schoolchildren on preventing obesity during the adiposity rebound period: a cross-over randomized cluster trial" and "Effectiveness of physical activity intervention to prevent obesity and improve academic performance in children with and without ADHD risk".

The two interventions are based on a cross-over randomized trial aimed to test the effectiveness of an intervention to promote physical activity in the school environment (MOVI-KIDS) during two-years in 22 schools (20 public and two private schools) in the provinces of Cuenca and Ciudad Real, Spain.

This principal subproject consisted of a mixed study including both the trial cited above and a nested qualitative study aimed to identify barriers and facilitators to physical activity in children in the school environment (social and family factors, urban planning, etc.), and produce knowledge about the perceptions of children, parents and teachers on how you can improve conditions of physical and social environment to facilitate physical activity.

The hypotheses of this third edition are that a multidimensional intervention promoting physical activity in children at the adiposity rebound period (4-7 years),in the school environment (MOVI-KIDS), lasting two-years, will to:

1. Reduce the body fat percentage in the intervention group versus the control group in 2%.
2. Improve the several components of fitness: aerobic capacity, strength, speed and agility.
3. Reduce the carotid intima-media thickness and
4. Reduce fat, increase fat free mass, and reduce sedentary behavior.

Inclusion Criteria:

• Schools with at least one full course of 3rd of early childhood education and one of 1st primary school.
• The Boards of Governors (community participatory organ in each school) give its approval to the intervention and measurements at the beginning and end of the course.
• Children 4 to 7 years old.
• Children's parents/caregivers will give their written consent to the children's participation.
• Collaboration in the family to respond to questionnaires on family leisure habits, sleeping, eating, getting around town, etc., included in the measurement protocol of this project.

Exclusion Criteria:

• Have a malformation that prevents learning of the Spanish language (or Spanish sign language).
• Have some kind of physical or mental disorder identified by parents or teachers that prevent physical activity.
• Have a chronic illness such as heart disease, diabetes or asthma, as determined by your pediatrician/family doctor -after analysis of the activities program- prevents participation in them.