Construct and criterion validity of muscle ultrasonography for assessment of skeletal muscle in patients recovering from COVID-19

Kirby P. Mayer, Kate Kosmac, Yuan Wen, Selina M. Parry, Sanjay Dhar, Sarah Foster, Jonathan Starck, Ashley A. Montgomery-Yates, Esther E. Dupont-Versteegden, Anna G. Kalema

Research output: Contribution to journalArticlepeer-review


Background: The purpose was to investigate the content, construct, and criterion validity of muscle ultrasound in a mixed cohort of participants recovering from mild and critical COVID-19. Methods: A secondary analysis of a prospective cross-sectional study was conducted on data obtained from a battery of muscle and physical function assessments including a muscle biopsy and muscle ultrasonography (US). Rectus femoris (RF) muscle thickness (mT), quadricep complex (QC) mT, RF muscle cross-sectional area (CSA) using 2D freeform trace and estimated from Feret’s diameter, and RF echo intensity (EI) were assessed with US. Muscle fiber CSA, fiber type, protein content in muscle fibers, extracellular matrix content (ECM; wheat-germ agglutin), and percent area of collagen in ECM (picrosirius red) were examined from vastus lateralis muscle biopsies. Spearman rho correlations (r) were performed to assess validity of ultrasound parameters. Results: Thirty-three individuals participated including 11 patients surviving critical COVID-19, 15 individuals recovering from mild-COVID, and 7 controls. There were several significant correlations between RF mT, QC mT, RF CSA, and RF EI with age, comorbid burden, body-mass index, and measures of muscle strength, muscle power, and physical function (range r = 0.35–0.83). RF Feret’s CSA correlated to CSA of type II muscle fibers (r = 0.41, p = 0.022) and the average size of all muscle fibers (r = 0.39, p = 0.031). RF EI was correlated with collagen in muscle ECM (r = 0.53, p = 0.003) and protein content in muscle tissue (r = −0.52, p = 0.012). Conclusion: Muscle size and quality measured using US has moderate content and construct validity, and to lesser extent, fair to moderate criterion validity in a mixed cohort of individuals recovering from COVID. Muscle ultrasound quality (EI) appears to be sensitive at detecting muscle dysfunction as it is associated with strength, power, physical function, and collagen distribution in a mixed group of individuals recovering from COVID-19.

Original languageEnglish
Article number1231538
JournalFrontiers in Physiology
StatePublished - 2023

Bibliographical note

Funding Information:
The project was supported by the Pilot Grant Program of the Office of Research and Scholarship of the College of Health Sciences, University of Kentucky. The project was supported by the NIH National Center for Advancing Translational Sciences through grant number UL1TR001998. KM was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institute of Health K23-AR079583. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Publisher Copyright:
Copyright © 2023 Mayer, Kosmac, Wen, Parry, Dhar, Foster, Starck, Montgomery-Yates, Dupont-Versteegden and Kalema.


  • ICU-acquired weakness
  • critical illness
  • muscle dysfunction
  • muscle ultrasound
  • muscle wasting
  • post-intensive care syndrome
  • skeletal muscle

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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