Citation

Carrier DR, Heglund NC, Earls KD. Science 1994; 265(5172): 651-653.

Affiliation

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912.

Copyright

(Copyright © 1994, American Association for the Advancement of Science)

DOI

unavailable

PMID

8036513

Abstract

Human feet and toes provide a mechanism for changing the gear ratio of the ankle extensor muscles during a running step. A variable gear ratio could enhance muscle performance during constant-speed running by applying a more effective prestretch during landing, while maintaining the muscles near the high-efficiency or high-power portion of the force-velocity curve during takeoff. Furthermore, during acceleration, variable gearing may allow muscle contractile properties to remain optimized despite rapid changes in running speed. Forceplate and kinematic analyses of running steps show low gear ratios at touchdown that increase throughout the contact phase.

Language: en