Abstract
BACKGROUND: Ultrasound imaging is important in many fields such as medicine, sports, and health sciences to assess parts of muscle structure (e.g., muscle thickness [MT]) or composition (subcutaneous tissue [Sub(T)]). OBJECTIVE: The aim of the present study was to investigate the intra- and inter-rater reliability of MT and Sub(T) measurements of the hip abductor muscles gluteus medius (GM) and tensor fascia latae (TFL). DESIGN: Cross-sectional study. METHOD: Twenty young adults participated in the study. Intra-rater reliability was established by measuring the same two images twice by the same rater, while inter-rater reliability was assessed between two raters by measuring the same two images for each muscle. For both intra- and inter-rater reliability, the reliability of the TFL and GM outcomes (MT- Sub(T)) were determined by the intraclass correlation coefficient (ICC), coefficient of variation (CV), standard error of the measurement (SEM), and Bland-Altman plots. RESULTS: For intra-rater reliability, variables of both muscles showed an excellent ICC (≥0.90), lower CV and SEM, and bias near zero. Inter-rater reliability also showed an excellent ICC for both variables and muscles (≥0.81) with lower CV, SEM, and bias. CONCLUSION: Therefore, these results provide strong evidence of a reliable measure of MT and Sub(T) from GM and TFL. The present study provides health care professionals and researchers increased confidence in using 2D ultrasound to assess the hip abductors muscles reliably.