Aim: The objective of the present study was to determine relationship between aerobic (cardiovascular) fitness and body composition in both non-overweight and overweight 12-year-old school boys.
Methods: A cross-sectional study was conducted in a random sample of 10 elementary schools. The study participants were a 170 healthy fifth-grade elementary school boys aged 11.9±0.4 years. Anthropometric data (height, body mass, waist circumference, abdominal skinfold thickness) were collected according to standard procedure. Total body fat and muscle mass percentage were assessed by bioimpedance analysis. Body Mass Index (BMI) age-specific cutoff points were used for overweight definition and boys were placed in two groups overweight and non-overweight. Aerobic fitness (VO2max) was assessed with the multistage shuttle-run fitness test. Boys were grouped into high (upper two quintiles) and low (lower two quintiles) aerobic fitness based on age distribution.
Results: Waist circumference, abdominal skinfold thickness and total body fat were lower while muscle mass percentage was higher in overweight boys with high aerobic fitness in comparison with boys at the same BMI category with low fitness level (P<0.05). Aerobic fitness was inversely correlated with body fat in the whole group of subjects (r=-0,57, P<0.05), with particularly high correlation between VO2max and muscle mass in overweight boys (r=0.68, P<0.05).
Conclusion: Indicators of local and total adiposity were lower in boys with high aerobic fitness. It seems that high aerobic fitness has is positively associated with body composition in overweight boys.