Physical activity and physical fitness in children and their relationship on body fat

Low levels of physical activity and physical fitness are risk factors of obesity and cardiovascular disease from childhood to adulthood. According to several studies, inactivity increases with the age of the school students. In Spain, according to results of the 2018 Report, only 34% of boys and 27% of girls aged 3 to 14 are active. This study aimed to compare differences between genders in body composition and PA; to analyse the relationship between the variables studied. Methods: This study used a non-experimental research design. PAQ-C questionnaire and ALPHA-Fitness tests were used. Descriptive analysis, correlation and linear regression gave the following results: boys had better scores in PA, and worse in BF percentage. PA in boys is related to aerobic capacity (r = 0.426, p < .01), BMI and BF (r = -0.368, and -0.323, p < .01 respectively). BF variability in boys (R 2 = 0.35) is determined by aerobic capacity (t = -4.161; p < .01) and lower-body explosive strength (t = -3.832; p < .01). Findings show an association between PA and the elements of PF studied, and an explanatory model of body fat based on aerobic capacity and lower-body explosive strength in boys.