July 29, 2009

Arm Swinging Saves Energy

Scientists have discovered that the reason we swing our arms while we walk can be attributed to our body's natural ability to conserve energy.

Scientists have long been puzzled over the reasons why humans swing their arms while walking. But a recent study conducted by researchers in the US and the Netherlands appears to have found that answer.

They found that it actually requires 12 percent more metabolic energy to hold arms still rather than swinging them while walking.

Researchers from the University of Michigan and Delft University of Technology studied 10 volunteers and a mechanical model to determine the metabolic cost of walking with a normal swing, an opposite-to-normal swing or with their arms not moving at all.

A so-called anti-swing walk, involving arms to swing with the steps of the corresponding leg, used 26 percent more energy, researchers added.

"Although arm swinging is relatively easy to achieve, its effect on energy use during gait is significant," researchers concluded in Wednesday's Proceedings of the Royal Society B.

"Rather than a facultative relic of the locomotion needs of our quadrupedal ancestors, arm swinging is an integral part of the energy economy of human gait."


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