[Effect of calcium on the temporal characteristics of muscle contraction].

It is shown that the shape of mechanical relaxation time spectrum of single glycerinated rabbit fibre m. psoas changed with calcium concentration. When increasing Ca++ of the rate constant of delayed tension development increases several times in the absence of inorganic phosphate. Addition of 10 mM of inorganic phosphate increases this rate constant and sharply decreases its calcium dependence. These data are discussed in terms of possible connection between cross-bridges by means of ATPase reaction product-inorganic phosphate.