Skinfold Thickness Pinch Size Can Interfere in the Estimation and Classification of Body Adiposity

Abstract

The objective was to verify the effect of pinch size on the absolute measure of skinfold thickness and on the consequent interference in the estimation and classification of the components of body adiposity. This was a cross-sectional study conducted with a sample of 29 subjects of both sexes aged 20 to 35 years. The study was conducted in the city of Fortaleza, Ceará, Brazil. Four measurement steps were performed at each site of the eight chosen skinfolds. The first step was performed with a subjective-landmark and the three subsequent steps with fixed-landmarks defined with an expanding secondary line at 2 cm intervals. Body adiposity components were estimated from the skinfold thickness measured at each landmark. Repeated measures ANOVA and Bland-Altman agreement analysis were applied. The subjective-landmark was chosen as the dependent variable. The 6 cm-landmark showed similarity and statistical agreement with the subjective-landmark for all skinfolds except the thigh, and with the sums of five and eight skinfolds. All fixed-landmarks showed agreement below the cut-off point for the percentile classification of subcutaneous adiposity and normative relative body fat. It is concluded that variation in the pinch size of skinfold thickness is a new and important source of technical error in anthropometric measurement.