title: Ultrasonographic assessment of human skeletal muscle size.
abstract: The measurement of human muscle size is essential when assessing the effects of training, disuse and ageing. The considered 'gold standard' for cross-sectional area measurements of muscle size is magnetic resonance imaging (MRI). However, MRI is costly and often inaccessible. The aim of the present study was to test the reproducibility and validity of a more accessible alternative method using ultrasonography (ULT). We examined the cross-sectional areas in the vastus lateralis muscle of six individuals. Axial-plane ULT scans were taken at given levels along the entire muscle length. The ULT scanning was repeated on different days (reliability) and validated against MRI-based measurements. Mean intraclass correlation coefficients were 0.998 for the reliability of ULT and 0.999 for the validity of ULT against MRI. The coefficient of variation values for cross-sectional area measurements assessed by six different experimenters were 2.1% and 0.8% for images obtained with ULT and MRI, respectively. The ULT method is a valid and reliable alternative tool for assessing cross-sectional areas of large individual human muscles. The present findings justify the application of the ULT method for the detection of changes throughout large muscles in response to training, disuse or as a consequence of sarcopenia.
authors.affiliation: Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Alsager Campus, Hassall Road, Alsager, Cheshire, ST7 2HL, UK. n.reeves@mmu.ac.uk
authors.forename: Neil D
authors.initials: ND
authors.lastname: Reeves
authors.forename: Constantinos N
authors.initials: CN
authors.lastname: Maganaris
authors.forename: Marco V
authors.initials: MV
authors.lastname: Narici
mesh_terms: D000368:Aged; D019412:Anatomy, Cross-Sectional; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D013223:Statistics as Topic / Q000295:instrumentation; D014463:Ultrasonography / Q000379:methods* / Q000706:statistics & numerical data