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5/15/2005

Handicapping athletes: Test offers new means of predicting speed

For generations, coaches and scouts have relied on stopwatches and their instincts to predict how fast an athlete could be.  Now, a Rice physiologist has proven a way to accurately predict runners' speeds for durations of time lasting from a few seconds to several minutes.

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In studies published in the Journal of Applied Physiology, researchers identify the physiological determinants of brief, all-out exercise performance and apply this information to develop a practical test for predicting performance and quantifying fitness.

The first study, titled " High-Speed Running Performance: A New Approach to Assessment and Prediction," was conducted by Peter Weyand, a physiologist in the kinesiology department at Rice University, Matthew Bundle with the Flight Laboratory at the University of Montana and Reed Hoyt at the U.S. Army Research Institute for Environmental Medicine, Biophysics and Biomedical Modeling.   Further tests by Weyand and Bundle appeared in a second article, titled "Energetics of High-Speed Running: Integrating Classical Theory and Contemporary Observations."

"There are two sources of metabolic energy," Weyand explains. "Aerobic energy can sustain an individual for an infinite amount of time. By contrast, anaerobic energy, used in shorter durations of activity, is finite — akin to energy in a battery. If you start pulling on it really fast, it gets used up quickly."  

The method Weyand and his colleagues use to predict all-out running speeds for efforts lasting from a few seconds to several minutes expand upon theories proposed by British physiologist and biophysicist Archibald Hill, the 1922 co-recipient of the Nobel Prize in medicine whose discoveries concerned the production of heat in muscles. Hill provided the original physiological explanation for the relationship between performance and duration. Using record performances from competitive foot racing and swimming, he observed that as the duration of an all-out effort increases from a few seconds to a few minutes, the speed that can be maintained decreases significantly. But with increases from a few minutes to a few hours, speed decreases relatively little.

Weyand and his colleagues sought to evaluate whether Hill's widely accepted ideas were quantitatively correct and, if so, to find practical ways to apply them. They developed a procedure that involved seven competitive runners of different event specialties, tested both on a treadmill and during overground (track) running. Using the measured values of the maximum speeds supported by anaerobic and aerobic power in conjunction with an exponential constant, the researchers predicted speeds of all-out treadmill trials to within an average of 2.5 percent and track trials to within 3.4 percent.

As a performance assessment, this new method offers an alternative to current tests of aerobic and anaerobic power. "The new tests allow the two basic sources of metabolic energy fueling performance to be assessed in a matter of minutes and outside the laboratory," Weyand says.

Weyand has been teaching biomechanics and physiology at Rice since 2003. His research on the relationships between the mechanics of movement, performance, metabolic energy expenditure and power also has been published in Science, Nature, The Proceedings of the National Academy of Sciences, the American Journal of Physiology: Regulatory, Integrative and Comparative Physiology and the Journal of Experimental Biology.

A graduate of Bates College, Weyand completed his Ph.D. in physiology from the University of Georgia.  

To learn more about this research, contact Weyand at pweyand@rice.edu or Margot Dimond in the Office of News and Media Relations at mdimond@rice.edu .

Research @Rice 2005