Background:‪The increasing problem of overweight and obesity in children is the reason for taking further actions leading to mass reduction, because, in contrast to adults, the consequences of this pathology in young people are still not well known. The intervention actions that can lead to reduction in mass are not easy to find in literature, and their long-term effects are unknown. The aim of this research was to define the changes in body composition of children with excess body mass after eight-week high intensity workout.Material and methods:‪The study was conducted on 47 children aged 9‒12 years who were overweight or obese, including 25 girls and 22 boys.Results:‪The following results were obtained: the percentage body fat decreased by 2.11% with great reduction in the visceral fat area of 7.86 cm², the decrease in fat mass by 1.44 kg, BMI decrease by 0.95 kg/m², the reduction of percentile in OLAF grids by 2.42 points. All of these results were statistically significant.Conclusions:‪The results of this study allow stating that: 1) the participants tolerated high intensity physical workout at the level of 70‒90% maximal heart rate (HR max) during 2 months of training, 2) systematic physical exercises caused positive changes in the body composition, 3) gender varied the scope of changes in some indicators



Author ORCID Identifier

Tomasz Dudziak https://orcid.org/ 0000-0001-9173-7988