Royal Society Publishing

The length–tension curve in muscle depends on lattice spacing

C. David Williams , Mary K. Salcedo , Thomas C. Irving , Michael Regnier , Thomas L. Daniel


Classic interpretations of the striated muscle length–tension curve focus on how force varies with overlap of thin (actin) and thick (myosin) filaments. New models of sarcomere geometry and experiments with skinned synchronous insect flight muscle suggest that changes in the radial distance between the actin and myosin filaments, the filament lattice spacing, are responsible for between 20% and 50% of the change in force seen between sarcomere lengths of 1.4 and 3.4 µm. Thus, lattice spacing is a significant force regulator, increasing the slope of muscle's force–length dependence.

  • Received March 19, 2013.
  • Accepted June 11, 2013.
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