Body composition (fat and lean, fat-free body mass, using hydrodensitometry and skinfolds); first measurements during childhood, adolescence, up to advanced age; also in athletes and obese subjects of all age categories), as related to dietary intake, physical activity regimes, functional capacity, physical performance and fitness, lipid metabolism variables, gross and fine motor skills. Special focus - preschool children, followed up from mentioned points of view, with regard to environmental conditions including physical activity, and health prognosis. - Experiments in laboratory animals focused on the actual and delayed consequences of various levels of physical activity (spontaneous and/or induced; exercise and/or hypokinesia), starting with earliest periods of life including fetal one. Delayed consequences concerning lipid metabolism in various organs, total body fat and lean, fat-free body mass ratio, size of different organs, cardiac microstructure and its sensitivity to noxi, etc.were studied up to the adult age. – Studies of obese subjects with joined metabolic and clinical problems as related to diet, physical activity level, biochemical and hormonal characteristics, psychological traits, etc..and the results of reduction treatment and prevention, especially during growth were also conducted.