Rules of nature's Formula Run: Muscle mechanics during late stance is the key to explaining maximum running speed.

摘要: Abstract The maximum running speed of legged animals is one evident factor for evolutionary selection—for predators and prey. Therefore, it has been studied across the entire size range animals, from smallest mites to largest elephants, even beyond extinct dinosaurs. A recent analysis relation between animal mass (size) showed that there seems be an optimal body masses in which highest terrestrial speeds occur. However, conclusion drawn analysis—namely, limited by fatigue white muscle fibres acceleration some theoretically possible speed—was based on coarse reasoning metabolic grounds, neglected important biomechanical factors basic muscle-metabolic parameters. Here, we propose a generic model investigate allometry running. incorporates biomechanically concepts: ground reaction force being counteracted air drag, leg with its gearing both into length change force, as well contraction velocity, includes muscle–tendon dynamics, inertia—with all them scaling mass. Put together, these concepts’ characteristics their interactions provide mechanistic explanation speed. This accompanies offering empirically found, overall speed: In bigger than cheetah or pronghorn, time any leg-extending needs settle, starting isometric at about midstance, concentric required becomes too long attainable within period moving midstance lift-off. Based our model, we, thus, suggest considering indicate inertia functionally significant locomotion. Furthermore, renders insights biological design principles such differences concept cats spiders, relevance multi-leg (mammals: four, insects: six, spiders: eight) designs emerging gaits. Moreover, expose completely new consideration regarding muscles’ energy consumption, during steady-state