TEST-RESTEST RELIABILITY OF BIOIMPEDANCE SPECTROSCOPY FOR THE ANALYSIS OF BODY COMPOSITION IN PHYSICALLY ACTIVE MALES

Abstract

Tyler W.D. Muddle1,2, Patrick M. Tomko1,2, Ryan J. Colquhoun1,2, Mitchel A. Magrini1, Nile F. Banks1,2, Nathaniel D.M. Jenkins1,2 1Applied Neuromuscular Physiology Laboratory 2Laboratory for Applied Nutrition and Exercise Science Oklahoma State University, Stillwater OK No previous studies, to our knowledge, have examined the reliability of bioimpedance spectroscopy (BIS) for the evaluation of body composition. PURPOSE: To evaluate the test-retest reliability of BIS for the assessment of total body water (TBW), extracellular water (ECW), and intracellular water (ICW) content, as well as fat mass (FM), fat-free mass (FFM), and body fat percentage (BF%) in physically active males. METHODS: Sixteen males (Mean ± SD, 25 ± 3 y, 90 ± 11 kg, 176 ± 6 cm) were assessed at two visits, separated by 2 – 7 days. During each visit, participants rested quietly for 3 – 5 min in a supine position with their arms abducted ≥ 30° away from their torso and legs separated prior to their assessment. Two single-tab electrodes were placed on the right side of the body 5 cm apart on both the dorsal surface of the wrist and dorsal surface of the ankle, respectively. The BIS device was used to estimate TBW, ECW, and ICW (liters; L) based on Cole modelling with Hanai mixture theory, which were then used to calculate FM (kg), FFM (kg), and BF%. Reliability was examined by calculating the intraclass correlation coefficient (ICC; model 2,1) and standard error of measurement (SEM). The coefficient of variation (CV) was calculated by expressing the SEM relative to the grand mean (%). The 95% confidence interval (CI) for each ICCwas calculated and used to test the null hypothesis that each ICC was equal to zero. Systematic variability was assessed for each variable via a paired t-test. RESULTS: Reliability statistics are displayed in Table 1. None of the dependent variables displayed systematic variability (p \u3e 0.05). ‘Excellent’ relative and absolute reliability was observed among all body water (ICC = 0.91 – 0.99; CVs = 1.08 – 3.50%) and body mass (ICC = 0.95 – 0.99; CVs = 1.10 – 6.99%) measurements. CONCLUSION: These results indicate that the BIS device used in this study allows for the reliable assessment of TBW, ECW, ICW, FM, FFM, and BF% in physically active men