1 kgf/cm2 — The Isometric Tension of Muscle Contraction: Implications to Cross-Bridge and Hydraulic Mechanisms

  • Reuven Tirosh
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 37)


Attention is drawn to experimental results from many laboratories which indicate that the isometric force (F) in the contraction of striated muscle fibers is linearly proportional to their variable cross-section area (A). Reversible swelling of intact, skinned, or glycinerated fibers can be induced by changes in tonicity, ionic strength or pH. In all cases where careful measurements of F and A are reported, the maximal isometric tension namely,
$$ {\rm{T}} = {\rm{F}}/{\rm{A}},{\mkern 1mu} {\rm{is}}{\mkern 1mu} {\rm{found}}{\mkern 1mu} {\rm{around}}{\mkern 1mu} 1{\rm{kgf}}/{\rm{c}}{{\rm{m}}^2},$$
even though F and A may change more than threefold for a given fiber at a certain length. These results seem to be independent of the fiber length or temperature. Thus, the isometric tension T in striated muscle does not depend on the number or the rate of the interacting cross-bridges.

This result of constant isometric tension, which has so far received little attention, is however, a simple prediction of the hydraulic mechanism which is proposed for muscle contraction. Therefore, the hydraulic model, which is based on the hypothesis of vectorial flux of energetic protons deserves serious consideration.


Force Generation Isometric Force Sarcomere Length Isometric Tension Myosin Filament 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Plenum Press, New York 1984

Authors and Affiliations

  • Reuven Tirosh
    • 1
  1. 1.Department of Cell BiologyThe Weizmann Institute of ScienceRehovotIsrael

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