Series elasticity in frog sartorius muscle subjected to stretch-shortening cycles.

Abstract

Changes in stiffness during stretch-shortening cycles were studied by applying prestretches of different rates and amplitudes on the tetanized sartorius muscle of the frog and measuring series elastic component characteristics during a subsequent quick release. Series elastic component stiffness was found to be dependent on the mechanical parameters of the stretching phase, and the so-called 'Cavagna effect' (increase in compliance) was rarely observed. The results are discussed in terms of improvement in muscle efficiency. Thus, an increase in stiffness during force generation will favour a better transmission of force and will reduce the coupling time whereas the opposite evolution during SEC recoil will allow a better release of potential energy.