Reports

Built for jumping: the design of the frog muscular system

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Science  21 Jan 1994:
Vol. 263, Issue 5145, pp. 370-372
DOI: 10.1126/science.8278808

Abstract

Frogs must generate a high level of mechanical power when they jump. The muscular system of frogs that jump is presumably designed to deliver these high powers. The length changes and activation pattern that muscles undergo during jumping were measured, and isolated muscle bundles were driven through this in vivo pattern. During jumping, muscles generated maximum power. Specifically, the muscle fibers (i) operated at optimal sarcomere lengths, (ii) operated at optimal shortening velocities, and (iii) were maximally activated during power generation. Thus, many different parameters must have evolved in concert to produce a system capable of this explosive jumping movement.