Bioelectrical impedance vectors analysis (BIVA) in older adults according to level of physical activity and muscle strength: a comparison of classic and specific approaches

Ismael Figueiredo Rabelo¹Shannon Hernon²Kieran F. Reid²Vanessa Ribeiro Dos Santos¹Melissa Antunes¹Vitor Cabrera Batista¹Andreia Bauermann-Vieira¹Luis Alberto Gobbo^1,3*

• ¹Skeletal Muscle Assessment Laboratory, School of Technology and Science, São Paulo State University (UNESP), Presidente Prudente, Brazil
• ²Laboratory of Exercise Physiology and Physical Performance, Brigham and Women's Hospital, Harvard Medical School, Boston, United States
• ³São Paulo State University, São Paulo, Brazil

This study evaluates classic and specific Bioelectrical Impedance Vector Analysis (BIVA) methods in older adults, analyzing the influence of physical activity levels and muscle strength. A cross-sectional design was employed with 187 participants (143 women, 44 men) aged 60 years and older. Bioelectrical impedance parameters were standardized for classic and segment-specific models. Physical activity was evaluated via the Baecke Habitual Physical Activity Questionnaire, while muscle strength was determined through handgrip dynamometry. Results indicated significant differences in impedance parameters (resistance and reactance) between classic and specific BIVA models, with higher values in the classic approach. Phase angle (PhA) differed significantly across activity and strength groups, highlighting gender-specific patterns: men exhibited higher PhA values due to lower resistance, while active women showed improved cellular integrity based on vector displacement. Despite these differences, both BIVA models demonstrated similar trends in functionality analyses, with stronger and more active individuals displaying superior bioelectrical health indicators. The findings underscore BIVA's utility for sarcopenia assessment, revealing the specific model's potential for refined body composition analysis. However, limitations include a predominantly female sample and the need for broader population validation. BIVA emerges as a promising tool for early detection and intervention in age-related functional decline, complementing established methods like grip strength testing.