Whole muscle length-tension relationships are accurately modeled as scaled sarcomeres in rabbit hindlimb muscles

Taylor M. Winters, Mitsuhiko Takahashi, Richard L. Lieber, Samuel R. Ward*

*Corresponding author for this work

Research output: Contribution to journalArticle

64 Scopus citations

Abstract

An a priori model of the whole active muscle length-tension relationship was constructed utilizing only myofilament length and serial sarcomere number for rabbit tibialis anterior (TA), extensor digitorum longus (EDL), and extensor digitorum II (EDII) muscles. Passive tension was modeled with a two-element Hill-type model. Experimental length-tension relations were then measured for each of these muscles and compared to predictions. The model was able to accurately capture the active-tension characteristics of experimentally-measured data for all muscles (ICC=0.88±0.03). Despite their varied architecture, no differences in predicted versus experimental correlations were observed among muscles. In addition, the model demonstrated that excursion, quantified by full-width-at-half-maximum (FWHM) of the active length-tension relationship, scaled linearly (slope=0.68) with normalized muscle fiber length. Experimental and theoretical FWHM values agreed well with an intraclass correlation coefficient of 0.99 (p<0.001). In contrast to active tension, the passive tension model deviated from experimentally-measured values and thus, was not an accurate predictor of passive tension (ICC=0.70±0.07). These data demonstrate that modeling muscle as a scaled sarcomere provides accurate active functional but not passive functional predictions for rabbit TA, EDL, and EDII muscles and call into question the need for more complex modeling assumptions often proposed.

Original languageEnglish (US)
Pages (from-to)109-115
Number of pages7
JournalJournal of Biomechanics
Volume44
Issue number1
DOIs
StatePublished - Jan 4 2011

Keywords

  • Length-tension relationship
  • Modeling
  • Muscle Function
  • Muscle architecture

ASJC Scopus subject areas

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

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