Selected somatic parameters and body composition as predictors of cardiorespiratory fitness among Polish adolescents aged 11–14

The aim of the study was to verify whether selected somatic parameters and components of body composition were significant predictors of cardiorespiratory fitness (CRF) among a potentially healthy Polish population of adolescents aged 11-14 years. The cross-sectional study was conducted on a group of 375 subjects (164 girls, and 211 boys). A 20 m shuttle run test (20 m SRT) was used to assess CRF. The total number of rounds was taken into account. Basic somatic parameters were measured: body mass (BM), body height (BH), waist circumference (WC), hip circumference (HC), body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR), and body composition components: body fat percentage (FM%), fat mass (FM kg), total body water (TBW), fat-free mass (FFM). Statistical analyses included basic statistical measures (mean and standard deviation) and Spearman rank correlation coefficient. Multiple linear regression analysis was performed to detect significant predictors of CRF. In each proposed model, the dependent variable was the number of rounds, and the independent variables were selected somatic parameters and components of body composition. More than half (65%) of the subjects had an average or lower level of CRF, and 35% of the population presented a good or above good level of CRF. The study showed a statistically significant negative correlation between BM, FM%, FM kg, HC, WC, BMI, WHR, WHtR and the number of laps in the total sample. The strongest correlation in the group of girls was noted for age (r = 0.34) and in the group of boys for FM% (r = <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>-</mml:mo> <mml:mn>0.52</mml:mn></mml:mrow> </mml:math> ). Each regression model presented proved to be statistically significant, and the significant predictors of CRF in the group of girls were age ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>R</mml:mi> <mml:mn>2</mml:mn></mml:msup> </mml:math> = 16%) and FM% ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>R</mml:mi> <mml:mn>2</mml:mn></mml:msup> </mml:math> = 6%). In the group of boys, the significant predictors of CRF were WHtR ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>R</mml:mi> <mml:mn>2</mml:mn></mml:msup> </mml:math> = 8%) and age ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>R</mml:mi> <mml:mn>2</mml:mn></mml:msup> </mml:math> = 2%). Estimating body fat distribution is useful in assessing cardiorespiratory fitness, and this in turn indicates its usefulness in preventive screening of school-aged adolescents.