Effect of negative work on the amount of positive work performed by an isolated muscle

Abstract

An isolated frog gastrocnemius tetanically stimulated performs a greater amount of positive work, during shortening at a given speed, if it has been stretched immediately before it was allowed to shorten. The increase of work performed is greater, the shorter the interval between stretching and shortening. A substantial amount of the work done on the contracted muscle during the stretching appears to be available during the shortening phase, as in elastic bodies. Note: (With the Technical Assistance of G. Orlando) tension-length diagram of isolated contracted muscle; elasticity of contracted muscle; efficiency of muscular contraction Submitted on May 4, 1964