PURPOSE: To determine the reliability of muscle thickness measurements of elbow and knee flexors and extensors using ultrasound, and to quantify the typical error associated to the measurements (TEM). METHODS: The test-retest reliability was determined in 15 apparently healthy volunteers (8 women, 34 ± 11 years, 76 ± 21 kg, 170 ± 10 cm). The images of elbow flexors (EF) and extensors (EE) and knee flexors (KF) and extensors (KE) were obtained using a two dimensional mode B ultrasound instrument with a 7.5 MHz transducer. Muscle thickness between the adipose tissue and bone interfaces were measured at anatomical landmarks previously identified and recorded to assure the exact site for the retest. RESULTS: ANOVA did not identify any significant differences between the repeated measurements. Intraclass correlation coefficients (ICC) of each pair of measure were EF = 0.970, EE = 0.971, KF = 0.555 e KE = 0.929 (P < 0.05 for all). The coefficients of variation were 3.9 %, 6.1 %, 6.6 % e 4.6 %, and TEM 1.3 mm, 1.6 mm, 4.9 mm e 1.9 mm, respectively, for the EF, EE, KF and KE thickness. Analysis of the Bland-Altman plot charts indicated that the variables did not present heterocedastic errors. CONCLUSION: EF, EE and KE muscle thickness measurements using the current method were highly reliable and can be used to measure and monitor changes in diet, physical training and rehabilitation programs. Nevertheless, KF measure should not be recommended since it presented low reliability and high TEM.
hypertrophy; reproducibility; skeletal muscle
