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 cat's 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.