Ostriches run fast because of 'springy' tendons

Oct 29, 2010 by Lin Edwards report
Human and ostrich hind-limb postures during mid-stance of running: (a,b) sagittal plane; (c,d) frontal plane. Image: [i]Journal of the Royal Society Interface[/i], doi:10.1098/​rsif.2010.0466

Australian and U.S. researchers studying the movement of ostriches have discovered the giant flightless birds can store double the elastic energy per step in their tendons than humans can. This considerably reduces the effort needed by the muscles, and enables the ostrich (and perhaps also the emu) to run twice as fast as humans while requiring only half the energy.

Leader of the study, Assistant Professor Jonas Rubenson of the School of Sports Science, Exercise and Health at the University of Western Australia, said the aim of the research was to find out what mechanical adaptations were made by species able to run fast and efficiently. He said that while lions and can outrun the ostrich on short sprints, they use a great deal of energy, and other species such as ostriches, antelopes and horses, can run fast over long distances.

Two hypotheses had been proposed to explain how some animals are able to run economically: the first was that they used a particularly efficient mechanical action in their limbs, and the second was the animals were able to store more elastic energy in their joints than sprinters.

To test these hypotheses the researchers fitted reflective markers to the joints of five humans and five tame ostriches to enable them to carry out a detailed analysis of their gait and movements as they ran on a custom-built running track 50 meters long. They also measured the forces applied to the ground during running. They selected the ostrich rather than the lighter Australian emu because the ostrich and humans have a similar mass, and because the ostrich is the fastest bird on the land.

The results demonstrated that both humans and ostriches need the almost exactly the same amount of mechanical work to swing their limbs during running, and the major difference was in the storage and release of energy by the . They calculated the release of this elastic energy generated 83% more work in the ostrich than in the human, which meant the ostrich uses less metabolic energy and is less fatigued.

The findings of the research, described in the Journal of the Royal Society Interface, may enable engineers to design better prosthetic limbs by focusing on elastic propulsion. They could also help robot researchers to design more agile robots. The results could also provide some insight into the evolution of bipedalism.

Explore further: Running robots of future may learn from world's best two-legged runners—birds

More information: Adaptations for economical bipedal running: the effect of limb structure on three-dimensional joint mechanics, Journal of the Royal Society Interface, Published online before print October 28, 2010, doi:10.1098/​rsif.2010.0466

Related Stories

China hatches 150 African ostriches

Aug 27, 2007

Breeders have successfully hatched one batch of African ostriches in the County of Nileke, northwest China's Xinjiang Uygur Autonomous Region.

Advances made in walking, running robots

May 26, 2010

Researchers at Oregon State University have made an important fundamental advance in robotics, in work that should lead toward robots that not only can walk and run effectively, but use little energy in the ...

Cockroaches offer inspiration for running robots

Dec 28, 2009

The sight of a cockroach scurrying for cover may be nauseating, but the insect is also a biological and engineering marvel, and is providing researchers at Oregon State University with what they call "bioinspiration" ...

Are high speed elephants running or walking?

Feb 12, 2010

Most animals don't think anything of breaking into a run: they switch effortlessly from walking to a high-speed bouncing run. But what about elephants? Their sheer size makes it impossible for them to bounce up in the air ...

Recommended for you

Science casts light on sex in the orchard

13 hours ago

Persimmons are among the small club of plants with separate sexes—individual trees are either male or female. Now scientists at the University of California, Davis, and Kyoto University in Japan have discovered ...

Four new dragon millipedes found in China

14 hours ago

A team of speleobiologists from the South China Agriculture University and the Russian Academy of Sciences have described four new species of the dragon millipedes from southern China, two of which seem to ...

Scientist creates automatic birdsong recognition app

18 hours ago

Dr Dan Stowell, an EPSRC Research Fellow in QMUL's School of Electrical Engineering and Computer Science, has used a grant from Queen Mary Innovation to develop a prototype for an app that turns his research ...

New research reveals fish are smarter than we thought

18 hours ago

(Phys.org) —A new study from researchers in our Department of Psychology with colleagues at Queen Mary University of London has reported the first evidence that fish are able to process multiple objects ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Deadbolt
not rated yet Oct 29, 2010
So... if we made the right set up of robot legs, embodying this springy principle, cyborg humans could run almost as fast as an ostrich?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.