Finite element model of intramuscular pressure during isometric contraction of skeletal muscle

Thomas R. Jenkyn, Bart Koopman, Peter Huijing, Richard L. Lieber, Kenton R. Kaufman

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

The measurement of in vivo intramuscular pressure (IMP) has recently become practical and IMP appears well correlated with muscle tension. A numerical model of skeletal muscle was developed to examine the mechanisms producing IMP. Unipennate muscle is modelled as a two-dimensional material continuum that is incompressible and nonlinearly anisotropic. The finite element technique is used to calculate IMP and muscle stress during passive stretch and during isometric contraction. A novel element models the contractile portion of muscle, incorporating sarcomere length-force and velocity-force relations. A range of unipennate muscle geometries can be modelled. The model was configured to simulate the rabbit tibialis anterior muscle over a range of lengths. Simulated IMP and stress results were validated against animal experimentation data. The simulation agreed well with the experimental data over the range of 0.8-1.1 of the optimal length. Severe pressure gradients were produced near the musculo-tendinous junctions while IMP was more uniform in the central muscle belly. IMP and muscle stress in relaxed (unstimulated) muscle increased nonlinearly with muscle length. IMP and stress in isometrically contracting muscle showed a local maximum at optimal length and were reduced at shorter lengths. At muscle lengths longer than optimal, stress and IMP increased predominately due to tension in the passive elastic structures.

Original languageEnglish (US)
Pages (from-to)4043-4061
Number of pages19
JournalPhysics in medicine and biology
Volume47
Issue number22
DOIs
StatePublished - Nov 21 2002

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

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