A Gender-Specific Associations of Body Composition with Physical Activity in a Sample of Czech Children

Abstract: The Czech Republic lacks body composition (BC) and physical activity (PA) data for children. Therefore, the purpose of the study was to analyze BC and PA in sample of Czech children and to find a gender-specific association between these variables. In this study we analyzed data of 129 children (75 girls) with mean age of 10.5±1.0 years. BC was estimated using multi-frequency bioelectrical impedance analysis (InBody 720) and PA was assessed using accelerometer ActiGraph GT3X. In entire sample, 19% of participants were classified as overweight and obese and 10% of participants spent more than 60 min/day in moderate-to-vigorous PA (MVPA). We found no significant difference between genders in fat mass (FM; P=0.91), fat mass percentage (FM%; P=0.58) and visceral adipose tissue (VAT; P=0.22). Boys had significantly more fat-free mass (FFM; P=0.04) then girls. Mean MVPA was significantly different (P=0.05) between girls (34.8±16.5 min/day) and boys (41.3±17.8 min/day). FM (rs=–0.25; P<0.01), FM% (rs=–0.26; P<0.01) and VAT (rs=–0.24; P=0.01) significantly decreased with increasing MVPA in entire sample, however this association seems to be a gender-specific. We have found significant associations of MVPA with FM (rs=–0.36; P<0.01), FM% (rs=–0.37; P<0.01) and with VAT (rs=–0.37; P<0.01) in girls, whereas no significant associations between BC and MVPA were found among boys (rs ranging from –0.14 to –0.11).The association of BC with MVPA seems to be a gender-specific. Although increase of MVPA was associated with decrease of body adiposity in both genders, we found significant associations only in girls.