Body fat in judokas: cross-validation of lohman’s equation

Abstract

Combat sports are disputed in weight categories. The greater the proportion of lean mass per kilogram of body mass, the greater a fi ghter’s capacity to exert force will be. Therefore, estimating percentage body fat (%F) is of fundamental importance for deciding in which category a fi ghter will compete. Therefore, the objective of this study was to verify the cross-validity of Lohman’s equation (LE) 7 for the estimation of %F in fi ghters. The sample comprised 30 male judokas, resident in the Distrito Federal, Brazil and with a mean age of 25.1±4.5 years, mean body mass of 81.8±12.5 kg and mean height of 176.3±7.1 cm. Hydrostatic weighing (HW) was used as the gold standard for cross-validation. The statistical criteria employed were those proposed by Lohman7 with the addition of residual score analysis.17 Correlation was high (r= 0.80) and signifi cant (p?0.0005). Both the constant error and the standard error of estimation were less than 3.5%. The %FLE (15.1±4.7) was signifi cantly different (p?0.0005) from the %FHW (11.9±4.2). Lohman’s equation signifi cantly overestimated the %F. The residual scores demonstrated a lack of agreement between %FLE and %FHW, of up to 8.5%F. This being so, Lohman’s equation does not exhibit cross-validity for this sample of judokas.