Email Print Share

News Release 05-161

The Mechanics of Foot Travel

With so many silly gaits to choose from, why have we adopted so few?

Comparison of body mass movement in the human walk and run.
View video

Computer simulations compare movement of the center of body mass in the human gait.


September 15, 2005

This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts.

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 of infinite two-legged locomotions has shown our favored modes of bi-pedal travel use the least amount of energy.

Indeed, in an article published in the current online edition of the British journal Nature, Cornell engineers Andy Ruina and Manoj Srinivasan compare the mechanics of walking and running with "many other strange and unpractised gaits." They used a set of computer models 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 another with the least muscle work," they report. "Why do people not walk or even run with a smooth level gait, like a waiter holding two cups brim-full of boiling coffee?"

The engineers' computer simulations conclude that walking is simply most energy efficient for travel at low speeds, and running is best at higher speeds. And, they report, a third walk-run gait is optimal for intermediate speeds, even though humans do not appear to take advantage of it.

The findings help to explain why the possible--but preposterous--gaits in the Monty Python sketch, "Ministry of the Silly Walks," have never caught on in human locomotion. The researchers add that extensions of this work might improve the design of prosthetic devices and energy-efficient bipedal robots.

-NSF-

Media Contacts
Leslie Fink, NSF, (703) 292-5395, email: lfink@nsf.gov

Program Contacts
Leon Esterowitz, NSF, email: lesterow@nsf.gov

Principal Investigators
Andy Ruina, Cornell University, email: ruina@cornell.edu
Manoj Srinivasan, Cornell University, email: ms285@cornell.edu

The U.S. National Science Foundation propels the nation forward by advancing fundamental research in all fields of science and engineering. NSF supports research and people by providing facilities, instruments and funding to support their ingenuity and sustain the U.S. as a global leader in research and innovation. With a fiscal year 2021 budget of $8.5 billion, NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and institutions. Each year, NSF receives more than 40,000 competitive proposals and makes about 11,000 new awards. Those awards include support for cooperative research with industry, Arctic and Antarctic research and operations, and U.S. participation in international scientific efforts.

mail icon Get News Updates by Email 

Connect with us online
NSF website: nsf.gov
NSF News: nsf.gov/news
For News Media: nsf.gov/news/newsroom
Statistics: nsf.gov/statistics/
Awards database: nsf.gov/awardsearch/

Follow us on social
Twitter: twitter.com/NSF and twitter.com/NSFspox
Facebook: facebook.com/US.NSF
Instagram: instagram.com/nsfgov