Objectives: To investigate the potential of segmental bioelectrical impedance analysis (BIA) for estimating whole-body composition in children.
Design: Strengths of relationships were determined between indices of impedance or specific resistivities of body segments and reference four-component model (4-CM) assessments of body composition.
Subjects: Eighteen boys and 19 girls aged 8-12 y.
Measurements: Whole-body and segment BIA and anthropometry were used to calculate impedance indices of the whole body and segments and specific resistivities of segments; total body water (TBW), fat-free mass (FFM) and body fat were assessed using the 4-CM.
Results: Segmental BIA indices were significantly related to body composition, provided that appropriate comparisons were undertaken for each index: impedance adjusted for unit segment length was better related to TBW and FFM, whereas segment specific resistivity was better related to body fat. Differences between body composition estimates obtained with the 4-CM and predicted using BIA were partly dependent on limb-to-trunk ratios of BIA indices.
Conclusion: Segmental BIA has potential for providing additional alternative approaches to the assessment of whole-body composition in children: (a) FFM and TBW were best related to impedance adjusted for segment length; (b) body fat was best related to segment specific resistivity; and (c) the relative influences of different segment BIA indices may be utilisable for generating more valid whole-body composition estimates.