Different frequencies to estimate bone mineral content from raw bioelectrical impedance data in adolescent soccer players: a critical analysis.

Introduction: Skeletal muscle mass, body cell mass, total body water (TBW), and bone mineral mass (BMC) are components of fat-free mass (FFM), which conducts electrical energy due to its high water and electrolyte content. Multifrequency bioelectrical impedance analysis (MF-BIA) has been used to predict FFM, and studies have explored its application for quantifying BMC, a subset of FFM. However, the accuracy of the BMC predicted using MF-BIA depends on the methodological rigor of the frequency selection. This study examined the relationships between BMC and raw MF-BIA data at different frequencies. Methods: The MF-BIA (SECA 515®) device obtained raw bioelectrical data at 5, 50, and 500 kHz. BMC was quantified using dual-energy X-ray absorptiometry (DXA). Multiple linear regression models and bioelectrical impedance vector analysis (BIVA) were applied to evaluate whole-body and segmental BMC relationships. Results: Male adolescent soccer players ( Conclusion: These findings indicate that MF-BIA could be a supplementary tool for studying BMC in adolescent athletes. However, its utility is constrained by prediction and interpretation errors, emphasizing the importance of careful frequency selection.