Bioimpedance phase angle reliability in Mexican college students

Abstract

Purpose: To determine phase angle reliability in Mexican college students. Methods: College students from the city of Tijuana, México, were recruited for this study. Volunteers were 26 males (Age = 22.7 ± 3.1 yr., Height = 172.8 ± 5.6 cm, Weight = 70.9 ± 11.7 kg) and 26 females (Age = 21.1 ± 2.2 yr., Height = 159.0 ± 7.1 cm, Weight = 60.8 ± 8.6kg). Participants arrived euhydrated to the testing session (Urine specific gravity = 1.005 ± 0.003) and were measured on a multi-frequency InBody 770 BIA device in two occasions separated by five minutes of seated resting. Body weight, %fat mass, muscle mass (kg) and PA were recorded and analyzed by repeated measures 2 (gender) x 2 (measures) ANCOVA, using hydration status and age as covariates. Intraclass correlation coefficient (ICC) and 95% confidence interval were used to determine reliability between measures. Results: Gender differences were found on PA (Males = 6.8 ± 0.1 vs. Females = 5.9 ± 0.1, p ≤ 0.0001), and muscle mass (Males = 31.9 ± 0.7 vs. Females = 23.2 ± 0.7 kg, p ≤ 0.0001). Significant (p ≤ 0.0001 for all) ICC reliability coefficients were found between pre- to post-measures of PA (r = 0.998, 95%CI = 0.996 to 0.999), %fat (r = 0.999, 95%CI = 0.998 to 1.00) and muscle mass (r = 1.00, 95%CI= 1.00 to 1.00). Conclusion: Young college students showed reliable BIA PA, muscle mass and %fat values following five minutes of seated resting. Mexican males showed higher muscle mass and PA than women after controlling for the influence of hydration and age.