Why Bouncy Legs Work Better  23 March 2010 8:01 pm  If
efficiency were all that matters, animals would hobble around
like pirates with two peg legs. That's because, mathematically
speaking, running with stiff legs requires less energy. But
humans and many other animals have "squishy" legs, and a new
simulation suggests why. When attached to real, floppy bodies,
so-called compliant legs prove more efficient, absorbing more
force and offering more stability in rough terrain. The finding
helps explain the long-puzzling paradox of why animals crouch
and bounce as they run and may change how researchers model
animal locomotion.  From loping camels to scuttling crabs,
animals move in a variety of ways. Centuries of research have
focused on why certain styles prevail--even Aristotle took a
stab at it. In the 1970s, researchers began using mathematics
and computers to model locomotion. That's when they ran into a
problem: models predicted that stiff legs were most efficient,
but real-world animals tended toward crouc