Estimation Method of Mechanochemical Constants of Skeletal Muscle in Man

A method for estimating mechanochemical constants of the skeletal muscle, such as elastic coefficient of the series elastic component (Es), heat constant (a) and rate constant of energy liberation (b), was developed. These constants were determined by comparing model responses with measured force caused by stretching or shortening of the thumb. Validity and usefulness of the method were assessed by applying it to the thumb flexor muscles in five healthy subjects. A special attention was paid to the nonlinear mechanical properties of the muscle varying with the intensity of the active state; that is, dynamic relations between force and length change over the interval when the constant contractile force was maintained were used for the estimation. The interval was from the onset of length perturbation to 50ms after that onset. Force response of the model closely agreed with the measured in human thumb. The parameter, Es, can be estimated accurately. While individual values of a and b could not be estimated uniquely, its combination k=(a+c)/b(c: constant) could be determined accurately, where the parameter k is coefficient of velocity-dependent force-loss of the contractile machinery.