Overlap of Subcutaneous Adiposity Across World Health Organization Body Mass Index-for-Age Categories and Anthropometric Correlates of Handgrip Strength in Children Aged 6–12 Years Participating in Organised Club Sport in Buenos Aires, Argentina

Background/Objectives: Body mass index (BMI) is the most widely used screening tool in paediatric nutritional assessment, but it does not measure body fat directly and conveys no information on muscular development. We aimed to (i) compare the sum of six skinfolds (Σ6ST) across World Health Organization (WHO) BMI-for-age categories, accounting for age; (ii) quantify the distributional overlap of Σ6ST between categories; (iii) examine how closely each individual skinfold tracks the remaining subcutaneous adiposity; and (iv) examine the associations of upper-limb girths with handgrip strength before and after adjustment for body size.