Characterization of load–length–velocity relationships of nine different skeletal muscles

A three-dimensional characterization of muscle load, length and velocity was obtained from nine muscles in the catʹs hind limb through contractions where the muscles shortened against inertial–gravitational loads. A model based on the load–length characteristic and second-order dynamics describes shortening velocity related to load and length under these conditions. We conclude that this model describes well contraction velocity as function of length and load under inertial–gravitational load conditions, with correlation coefficients higher than 0.9 in most of the tested muscles.