Effect of position and exercise on measurement of muscle quantity and quality: Towards a standardised pragmatic protocol for clinical practice

Carly Welch, Zeinab Majid, Isabelle Andrews, Zaki Hassan-Smith, Vicky Kamwa, Hannah Picton, Daisy Wilson, Thomas A. Jackson

Research output: Contribution to journalArticlepeer-review


Background:  Ultrasonography is an emerging non-invasive bedside tool for muscle quantity/quality assessment; Bioelectrical Impedance Analysis (BIA) is an alternative non-invasive bedside measure of body composition, recommended for evaluation of sarcopenia in clinical practice. We set out to assess impact of position and exercise upon measures towards protocol standardisation.

Methods:  Healthy volunteers aged 18-35 were recruited. Bilateral Anterior Thigh Thickness (BATT; rectus femoris and vastus intermedius), BATT: Subcutaneous Ratio (BATT:SCR), and rectus femoris echogenicity were measured using ultrasound and BIA was performed; 1) lying with upper body at 45° (Reclined), 2) lying fully supine at 180o (Supine), 3) sat in a chair with upper body at 90o (Sitting), and 4) after exercise Reclined. Variability of Skeletal Muscle Mass (SMM) by two different equations from BIA (SMM-Janssen, SMM-Sergi), phase angle, fat percentage, and total body (TBW), extracellular (ECW), and intracellular water (ICW) were assessed.

Results:  Forty-four participants (52% female; mean 25.7 years-old (SD 5.0)) were recruited. BATT increased from Reclined to Sitting (+ 1.45 cm, 1.27-1.63), and after exercise (+ 0.51, 0.29-0.73). Echogenicity reduced from Reclined to Sitting (- 2.1, - 3.9 - -0.26). SMM-Sergi declined from Reclined to Supine (- 0.65 kg, - 1.08 - - 0.23) and after exercise (- 0.70 kg, - 1.27 - -0.14). ECW increased from Reclined to Sitting (+ 1.19 L, 0.04-2.35). There were no other statistically significant changes.

Conclusion:  Standardisation of protocols is especially important for assessment of muscle quantity by ultrasonography; BIA measurements may also vary dependent on the equations used. Where possible, participants should be rested prior to muscle ultrasonography and BIA, and flexion of the knees should be avoided.
Original languageEnglish
Article number3
Number of pages8
JournalBMC sports science, medicine & rehabilitation
Publication statusPublished - 7 Jan 2021

Bibliographical note

Copyright © The Author(s), 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (https://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.


  • Sarcopenia
  • Diagnostic imaging
  • Electric impedance
  • Muscles


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