Prediction of Somatotype from Bioimpedance Analysis in Elite Youth Soccer Players

The accurate body composition assessment comprises several variables, causing it to be a time consuming evaluation as well as requiring different and sometimes costly measurement instruments. The aim of this study was to develop new equations for the somatotype prediction, reducing the number of normal measurements required by the Heath and Carter approach. A group of 173 male soccer players (age, 13.6 +/- 2.2 years, mean +/- standard deviation; body mass index, BMI, 19.9 +/- 2.5 kg/m(2)), members of the academy of a professional Italian soccer team participating in the first division (Serie A), participated in this study. Bioelectrical impedance analysis (BIA) was performed using the single frequency of 50 kHz and fat-free mass (FFM) was calculated using a BIA specific, impedance based equation. Somatotype components were estimated according to the Heath-Carter method. The participants were randomly split into development (n = 117) and validation groups (n = 56). New anthropometric and BIA based models were developed (endomorphy = -1.953 - 0.011 x stature(2)/resistance + 0.135 x BMI + 0.232 x triceps skinfold, R-2 = 0.86, SEE = 0.28; mesomorphy = 6.848 + 0.138 x phase angle + 0.232 x contracted arm circumference + 0.166 x calf circumference - 0.093 x stature, R-2 = 0.87, SEE = 0.40; ectomorphy = -5.592 - 38.237 x FFM/stature + 0.123 x stature, R-2 = 0.86, SEE = 0.37). Cross validation revealed R-2 of 0.84, 0.80, and 0.87 for endomorphy, mesomorphy, and ectomorphy, respectively. The new proposed equations allow for the integration of the somatotype assessment into BIA, reducing the number of collected measurements, the instruments used, and the time normally required to obtain a complete body composition analysis.