A spring in your step: some is good, more is not always better.

摘要

when humans and other animals run and hop, they operate with muscle efficiencies nearly twice those observed during cycling (2, 4). This "free energy" is due to the storage and return of elastic energy in muscles and tendons during the stretch-shorten cycles of landing and takeoff (1). If spring-like tendons and muscles can save substantial energy, could artificial springs added to the legs further reduce the metabolic cost of locomotion?