Despite having the bones and muscles to perform a variety of gaits,human beings have developed an overwhelming preference for just two:walking and running. Now, computer analysis that allows simulation ofinfinite two-legged locomotions has shown our favored modes of bi-pedaltravel use the least amount of energy.
Indeed, in an article published in the current online edition of theBritish journal Nature, Cornell engineers Andy Ruina and ManojSrinivasan compare the mechanics of walking and running with "manyother strange and unpractised gaits." They used a set of computermodels that simulated physical measurements such as leg length, force,body velocity and trajectory, forward speed and work.
"We wish to find how a person can get from one place to anotherwith the least muscle work," they report. "Why do people not walk oreven run with a smooth level gait, like a waiter holding two cupsbrim-full of boiling coffee?"
The engineers' computer simulations conclude that walking issimply most energy efficient for travel at low speeds, and running isbest at higher speeds. And, they report, a third walk-run gait isoptimal for intermediate speeds, even though humans do not appear totake advantage of it.
The findings help to explain why the possible--butpreposterous--gaits in the Monty Python sketch, "Ministry of the SillyWalks," have never caught on in human locomotion. The researchers addthat extensions of this work might improve the design of prostheticdevices and energy-efficient bipedal robots.
Cite This Page: