The relationship between physical activity, physical fitness and fatness in 3-6 years old boys and girls: a cross-sectional study.

Background: Physical activity (PA), fatness and fitness in children and teenagers have been associated with short and long-term health benefits. However, little research analyzing these variables focuses on the preschool education stage. Thus, the objective of this research is to study the relationship between PA, fatness and fitness in 3-6 years old boys and girls. Methods: This cross-sectional study includes 150 boys and girls at age between 3 and 6 years. Fatness and fitness were assessed using a PREFIT (FITness testing in PREschool children) battery as well as the sit and reach test. PA levels were measured using accelerometers for 7 days. Results: Higher PA levels were related to better fitness values. In addition, differences were found in the PA levels between boys and girls. However, PA subcomponents were not related to fatness. Furthermore, there were no significant differences in fitness tests between underweight, normal-weight and over-weight children, except in handgrip strength. Conclusions: The few studies that have analyzed the relationship between fatness, fitness and PA in preschool have revealed controversial results. However, our study is in accordance with the majority of studies which prove that PA is associated with better fitness performances in preschool children. Since fitness is an important indicator of health, schools and parents should encourage children to practice more daily PA, especially girls, who are less active than boys. However, the discrepancy about the relationship between PA and fatness between the results of the different research highlights the necessity of carrying out further studies that analyze the relationship between these 3 variables separately in each age group (3, 4, 5 and 6 years). This is due to the fact that associations were stronger in older children rather than in younger children.