Body knows how to walk far with least effort: study

March 21st, 2009 - 2:28 pm ICT by IANS  

Washington, March 21 (IANS) If your body is telling you that your pace is a little too fast or a little too slow, it may be right.
A new study by Karen Steudel of the University of Wisconsin-Madison and Cara Wall-Scheffler of Seattle Pacific University shows how the body knows the optimal pace at which it can cover the greatest distance with the least effort.

The result debunks the popular view that running has the same metabolic cost per unit of time no matter what the speed. In other words, the energy needed to run a given distance is the same whether sprinting or jogging.

Though sprinting feels more demanding in the short term, the longer time and continued exertion required to cover a set distance at a slower pace were thought to balance out the difference in metabolic cost, said Steudel, a zoology professor.

However, Steudel and Wall-Scheffler have now shown that the energetic demands of running change at different speeds.

“What that means is that there is an optimal speed that will get you there the cheapest, metabolically speaking,” Steudel said.

The most efficient running speed determined in the study varied between individuals but averaged about 8.3 miles per hour for males and 6.5 miles per hour for females in a group of nine experienced amateur runners, said a Wisconsin-Madison release.

Much of the gender difference may be due to variations in body size and leg length, which have been shown to affect running mechanics, Steudel said. In general, larger and taller runners had faster optimum speeds.

Interestingly, the slowest speeds - around 4.5 miles per hour, or about a 13-minute mile - were the least metabolically efficient, which the researchers attributed to the gait transition between walking and running.

The study was published online in the Journal of Human Evolution.

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