Physical development as per results produced by bioelectrical impedance analysis (BIA) for estimating body composition depending on sex and age of schoolchildren aged 7–16 years

The research goal was to estimate physical development of schoolchildren as per data of bioelectrical impedance analysis (BIA) of body composition depending on their sex and age. Physical activity (PA) is an important factor in providing physical welfare of schoolchildren and this makes the present research relevant today. We examined 604 schoolchildren. At present a share of schoolchildren who have physical activity with its duration corresponding to the WHO recommendations doesn’t exceed 45%. We established an inverse correlation between a share of Skeletal muscle mass (SMM) and age. The determination coefficient which showed a variability a share of SMM and fat mass depending on a combination of PA regularity and duration didn’t exceed 0.06. It grew up to 0.19 after we assessed influence exerted by schoolchildren’s age on the absolute value of BMM share. A contribution made by age to this parameter was by 8.0 times higher among boys than among girls. We detected an age-specific decline in a probability of lower SMM share which was by up to 11.8 times lower among boys than among girls. These established sex-related differences in probable age-specific decrease in physical development make BIA a more valuable source of information for motivating schoolchildren to have more PA and improve their health