Can we just forget about pennation angle?

Richard L. Lieber*

*Corresponding author for this work

Research output: Contribution to journalShort surveypeer-review

7 Scopus citations


Skeletal muscle design studies, based on anatomical structure, extend back several hundred years. Accurate anatomical drawings show that many muscle fibers are oriented at an angle relative to a muscle's axis of force generation. This pennation angle has been reported in the skeletal muscle biomechanics literature, primarily in the context of trying to understand muscle force generation. In this perspective, I will describe several discoveries that changed my understanding of pennation and I will suggest that muscle pennation has little if any functional significance. I believe that the correct view of pennation is that it represents a packing strategy whereby short fibers can be packed into a limited volume. While surface pennation angle is easily measured, is very descriptive, and changes during force generation, I believe it has no functional significance.

Original languageEnglish (US)
Article number110954
JournalJournal of Biomechanics
StatePublished - Feb 2022


  • Fiber length
  • Fiber type
  • Mulitpennate
  • Muscle architecture
  • Physiological
  • Ross-sectional area
  • Unipennate

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Orthopedics and Sports Medicine
  • Rehabilitation


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