Skip to main content
Log in

Echo intensity as an indicator of skeletal muscle quality: applications, methodology, and future directions

  • Invited Review
  • Published:
European Journal of Applied Physiology Aims and scope Submit manuscript

Abstract

Purpose

This narrative review provides an overview of the current knowledge of B-mode ultrasound-derived echo intensity (EI) as an indicator of skeletal muscle quality.

Method

PubMed and Google Scholar were used to search the literature. Advanced search functions were used to find original studies with the terms ‘echo intensity’ and/or ‘muscle quality’ in the title and/or abstract. Publications that conceptually described muscle quality but did not include measurement of EI were not a focus of the review.

Result

Importantly, the foundational premise of EI remains unclear. While it is likely that EI reflects intramuscular adiposity, data suggesting that these measurements are influenced by fibrous tissue is limited to diseased muscle and animal models. EI appears to show particular promise in studying muscular aging. Studies have consistently reported an association between EI and muscle function, though not all chronic interventions have demonstrated improvements. Based on the existing literature, it is unclear if EI can be used as a marker of muscle glycogen following exercise and nutritional interventions, or if EI is influenced by hydration status. Inconsistent methodological approaches used across laboratories have made comparing EI studies challenging. Image depth, rest duration, participant positioning, probe tilt, and the decision to correct for subcutaneous adipose tissue thickness are all critical considerations when interpreting the literature and planning studies.

Conclusion

While some areas show conflicting evidence, EI shows promise as a novel tool for studying muscle quality. Collaborative efforts focused on methodology are necessary to enhance the consistency and quality of the EI literature.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2

Similar content being viewed by others

Abbreviations

EI:

Echo intensity

MRI:

Magnetic resonance imaging

References

Download references

Author information

Authors and Affiliations

Authors

Contributions

Both authors contributed equally to all aspects of this review.

Corresponding author

Correspondence to Matt S. Stock.

Ethics declarations

Conflict of Interest

The authors declare no conflicts of interest in the reporting of this research.

Additional information

Communicated by Michael Lindinger.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Stock, M.S., Thompson, B.J. Echo intensity as an indicator of skeletal muscle quality: applications, methodology, and future directions. Eur J Appl Physiol 121, 369–380 (2021). https://doi.org/10.1007/s00421-020-04556-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00421-020-04556-6

Keywords

Navigation