Prediction of the cardiac muscle force-velocity relation from its force-time and force-length relations

The force-velocity relation for cardiac muscle fibers can be calculated from a proposed constitutive law based on force-time and force-length data. The calculated force-velocity relation agrees quite well with the measured force-velocity relation obtained from a quick release of sarcomere controlled rat cardiac trabeculae. The theory confirms the measured linear relationship between maximal velocity of sarcomere shortening and sarcomere length. The implication is that the force-velocity relation is not an independent property, and therefore need not be explicitly included as a rheological element in the constitutive law.