THE DECREMENT IN MUSCULAR FORCE WITH INCREASING SPEED OF SHORTENING

Abstract

Contractions of the maximally tetanized gastrocnemius of the decerebrate cat against inertia disks were recorded photographically using up to 180 exposures a sec. The forces exerted were calculated from the displacements by numerical differentiation, and compared with the isometric forces measured by a torsion wire myograph. Results with 15 cats show that the ratio of the difference between the isometric and isotonic forces to the speed of shortening was constant over a part of the contraction, the value of the constant depending on the equivalent mass of the inertia disk used. The results partially support a viscosity theory of Hill (J. Physiol. 56, 28 [1922]).