If you’ve ever visited a dog park, you may have noticed that a chihuahua tires much more quickly than a German shepherd. That does not occur just because a small dog takes more steps to cover the same amount of ground, says Peter Weyand, associate professor of applied physiology and biomechanics in SMU’s Annette Caldwell Simmons School of Education and Human Development.
In his research into animal and human physiology, Weyand has studied the impact of such factors as muscular force and the amount of time limbs are in contact with the ground on the energy cost of walking and running.
His years of research on creatures ranging from goats to antelopes to kangaroos indicate that smaller animals expend much more energy per pound to locomote. For example, a mouse expends 30 times more energy than an elephant in proportion to their weights, while human children use about twice as much energy as their parents to cover the same distance, he says.
Weyand and colleagues have found that one of the essential determinants of energy expenditure, fatigue rates and performance is the amount of time muscles are active to apply force to the ground, bicycle pedals or other external objects.
“This holds true whether you are a chihuahua, a German shepherd, Usain Bolt or a couch potato,” he says. Shorter times mean higher rates of energy expenditure and more rapid fatigue, but they are also necessary for high-end performance.
Now the holder of a patent on his methods, Weyand has explained the limits of human and animal running performance for the History Channel, CNN, the Canadian Broadcasting Corporation, NHK Television Japan and a host of other media outlets. He monitored sprinter Michael Johnson’s running mechanics in a special feature for NBCOlympics.com during the 2000 Athens games and has provided live commentary for the Boston Marathon.
Weyand’s research is funded in part by the U.S. Army Medical Research and Materiel Command, which hopes to develop quick methods to assess and monitor soldiers’ physical fitness to help improve their overall healthcare. He’s also helping to develop a new SMU undergraduate major in applied physiology and sports management.
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Annette Caldwell Simmons School of Education and Human Development