Peter Weyand

Research: New SMU study connects running motion to ground force

SMU researchers have developed a concise new explanation for the basic mechanics involved in human running. Their research has immediate application for running performance, injury prevention, rehab and the individualized design of running shoes, orthotics and prostheses.

The work integrates classic physics and human anatomy to link the motion of individual runners to their patterns of force application on the ground – during jogging, sprinting and at all speeds in between.

The approach could enable the use of individualized gait patterns to optimize the design of shoes, orthoses and prostheses according to biomechanics experts Kenneth Clark, Laurence Ryan and Peter Weyand, who authored the new study.

The ground force-time patterns determine the body’s motion coming out of each step and therefore directly determine running performance. The impact portion of the pattern is also believed to be a critical factor for running injuries.

“The human body is mechanically complex, but our new study indicates that the pattern of force on the ground can be accurately understood from the motion of just two body parts,” said Clark, first author on the study and currently an assistant professor in the Department of Kinesiology at West Chester University in West Chester, Pennsylvania.

“The foot and the lower leg stop abruptly upon impact, and the rest of the body above the knee moves in a characteristic way,” Clark said. “This new simplified approach makes it possible to predict the entire pattern of force on the ground — from impact to toe-off — with very basic motion data.”

> Read the full story at the SMU Research blog

Research: The speed secrets of super sprinters

The world’s fastest sprinters have unique gait features that account for their ability to achieve fast speeds, according to two new studies from SMU’s Annette Caldwell Simmons School of Education and Human Development.

The new findings indicate that the secret to elite sprinting speeds lies in the distinct limb dynamics sprinters use to elevate ground forces upon foot-ground impact.

“Our new studies show that these elite sprinters don’t use their legs to just bounce off the ground as most other runners do,” said human biomechanics expert Ken Clark, a researcher in the SMU Locomotor Performance Laboratory and lead author on the studies. “The top sprinters have developed a wind-up and delivery mechanism to augment impact forces. Other runners do not do so.”

The new findings address a major performance question that has remained unanswered for more than a decade. Previous studies had established that faster runners attain faster speeds by hitting the ground more forcefully than other runners do in relation to their body weight. However, how faster runners are able to do this was fully unknown. That sparked considerable debate and uncertainty about the best strategies for athletes to enhance ground-force application and speed.

“Elite speed athletes have a running pattern that is distinct,” Clark said. “Our data indicate the fastest sprinters each have identified the same solution for maximizing speed, which strongly implies that when you put the physics and the biology together, there’s only one way to sprint really fast.”

The critical and distinctive gait features identified by the study’s authors occur as the lower limb approaches and impacts the ground, said study co-author and running mechanics expert Peter Weyand, director of the Locomotor Performance Lab.

“We found that the fastest athletes all do the same thing to apply the greater forces needed to attain faster speeds,” Weyand said. “They cock the knee high before driving the foot into the ground, while maintaining a stiff ankle. These actions elevate ground forces by stopping the lower leg abruptly upon impact.”

The new research indicates that the fastest runners decelerate their foot and ankle in just over two-hundredths of a second after initial contact with the ground.

The findings are reported in the Journal of Applied Physiology in the article, “Are running speeds maximized with simple-spring stance mechanics?” It appears online at Physiology.org in advance of appearing in the print journal.

Written by Margaret Allen

> Read the full story at the SMU Research blog

Faculty in the News: March 8, 2011

Jake Batsell on CBS-11 NewsJake Batsell, Journalism, Meadows School of the Arts, provided expertise for a CBS-11 News story on tweeting and sports that was broadcast March 6, 2011. Watch Jake Batsell on CBS-11. video

Ed Fox, JCPenney Center for Retail Excellence, Cox School of Business, talked about the possible effects of rising commodity prices on Dallas-area consumers with The Dallas Morning News Feb. 22, 2011.

Bud Weinstein, Maguire Energy Institute, wrote that the current turmoil in the Middle East should be taken as a sign the United States should develop and maintain a complete portfolio of domestic energy sources in an article that appeared in The Hill Feb. 22, 2011. He also wrote about the potential of natural gas locked in shale formations in a story published by The Washington Examiner Feb. 18, 2011. In addition, he wrote about this resource’s potential impact on the Texas economy in a Fort Worth Star-Telegram article published Feb. 28, 2011.

Cal Jillson, Political Science, Dedman College, talked about the political implications of Texas’ changing demographics with The Houston Chronicle Feb. 18, 2011, and with The New York Times Feb. 25, 2011. He also discussed with The Canadian Press the political fallout from President Obama’s instruction to the U.S. Department of Justice to stop defending the Defense of Marriage Act, which prohibits same-sex marriage. The article was published Feb. 28, 2011, and appeared on numerous Canadian news sites.

Peter Weyand, Applied Physiology and Wellness, Annette Caldwell Simmons School of Education and Human Development, provided expertise for a story about how fast humans may eventually be able to run that appeared on National Public Radio Feb. 19, 2011.

Linda Eads, Dedman School of Law, talked about Texas lawyers’ vote against proposed amendments to the state bar’s Disciplinary Rules of Professional Conduct with Texas Lawyer Feb. 17, 2011.

John Attanasio, Dean, Dedman School of Law, provided expertise for a National Law Journal story on the successes of an SMU program that pays law firms to “test drive” new Law School graduates. The article appeared in the Feb. 28, 2011 edition.

Research Spotlight: How much energy does it take to walk?

Stock photo of family walking through woodsAny parent that takes their kid out for a walk knows that children tire more quickly than adults – but why is that? Do kids and small adults walk differently from taller people, or do they tire faster for some other reason?

SMU researcher Peter Weyand is fascinated by the effect that body size has on physiological function. To find answers, he has teamed up with Maurice Puyau and Nancy Butte, from the USDA/ARS Children’s Nutrition Research Center at Baylor College of Medicine, and undergraduate Bethany Smith.

Together they decided to measure the metabolic rates of children and adults, ranging from 5 to 32 years old, weighing between 15.9 kilograms and 88.7 kilograms and ranging in height from 1.07 meters to 1.83 meters, to try to find out why larger people are more economical walkers than smaller people.

Weyand and his colleagues publish their discovery that walkers of all heights use the same amount of energy per stride, making short people less economical because they take more steps. They also derive a fundamental equation to calculate exactly how much energy walkers use with direct applications in all walks of life.

The team published its discovery in the article “The mass-specific energy cost of human walking is set by stature” in the current issue of The Journal of Experimental Biology.

First Weyand and colleagues filmed male and female volunteers as they walked on a treadmill at speeds ranging from a slow 0.4 meters per second up to 1.9 meters per second. Meanwhile, they simultaneously measured the walkers’ oxygen consumption and carbon dioxide production rates to obtain their total metabolic rate.

Next the team calculated the amount of energy that each person used for walking by subtracting the basal metabolic rate (energy required to maintain the body’s basic metabolic functions) from the total metabolic rate measured while walking.

Finally, the team compared the way each person walked, measuring the walkers’ stride lengths, stride durations and the proportion of each stride they spent in contact with the ground (duty factor) to find out if large and small people walk differently.

Analysing the walkers’ styles, the team found that all of them moved in exactly the same way regardless of their height. Essentially, if you scaled a 5-year-old up to 2 meters, the giant child would walk in exactly the same way as a 2-meter-tall adult. So large people are not more economical because they walk differently from smaller people.

Next the team calculated the metabolic cost of a stride as each walker moved at their most economical pace and they discovered that walkers use the same amount of energy per stride regardless of their height. So, big people do not become more economical because they walk in a more economical style. Something else must account for their increased economy.

Finally, the four scientists plotted the walkers’ heights against their minimum energy expenditure and they were amazed when they got a straight line with a gradient of almost -1. The walkers’ energy costs were inversely proportional to their heights, with tall people walking more economically than short/smaller people because they have longer strides and have to take fewer steps to cover the same distance. So smaller people tire faster because each step costs the same and they have to take more steps to cover the same distance or travel at the same speed.

Peter Weyand and Oscar PistoriusBased on this discovery the group derived an equation that can be used to calculate the energetic cost of walking.

“The equation allows you to use your height, weight and distance walked to determine how many calories you burn,” says Weyand (at left in photo), associate professor of applied physiology and biomechanics in SMU’s Annette Caldwell Simmons School of Education and Human Development.

The equation could also be built into popular pedometers to provide users with a more realistic idea of how many calories they expend walking throughout the day. Finally, the team is keen to extend the equation to calculate metabolic costs at any speed.

“This has clinical applications, weight balance applications and the military is interested too because metabolic rates influence the physiological status of soldiers in the field,” explains Weyand.

Written by Kathryn Knight, The Company of Biologists

> Read more from the SMU Research blog

Faculty in the News: April 27, 2010

Jasper Smits, Psychology, Dedman College, discussed his research on how exercise can help get rid of anxiety with USA Today April 26, 2010.

Peter Weyand, Applied Physiology and Wellness, Annette Caldwell Simmons School of Education and Human Development, discussed the recent selection of single-amputee distance runner Amy Palmiero-Winters to the U.S. track team for an article that appeared in USA Today April 26, 2010.

Mary Spector, Dedman School of Law, talked about issues that arise when debt-collection companies use litigation to collect past-due bills for an article that appeared in The New York Times April 22, 2010.

Cal Jillson, Political Science, Dedman College, talked about civil-rights ramifications in the case of a gay couple seeking a divorce in Texas with The Fort Worth Star-Telegram April 20, 2010. He also discussed the popularity – and speaking fees – of Sarah Palin with the Star-Telegram April 19, 2010.

Alan Bromberg, Dedman School of Law, talked about the U.S. Securities and Exchange Commission’s fraud suit against Goldman Sachs with CNN Money April 19, 2010.

Bernard Weinstein, Maguire Energy Institute, Cox School of Business, wrote about creating a nuclear renaissance by reprocessing nuclear fuel in The Fort Worth Star-Telegram April 17, 2010.

Brian Bruce, EnCap Investments & LCM Group Alternative Asset Management Center, Cox School of Business, discussed how volatile markets have pushed some to invest in gold and jewels for an article published in The Chicago Tribune April 14, 2010.

David Meltzer, Anthropology, Dedman College, and Vance Holliday of the University of Arizona discussed how Paleoindians coped with climate change 11,000 years ago with Science News April 12, 2010.

Stan Wojewodski, Theatre, Meadows School of the Arts, discussed his career and his work with Dallas’ Undermain Theatre as part of a profile that appeared in The Dallas Morning News April 10, 2010. He becomes chair of the Meadows Division of Theatre in Fall 2010.

Carolyn Macartney, Cinema-TV, Meadows School of the Arts, discussed her upcoming film about the life of her grandmother – a former Wild West sharpshooter who was billed as Wanda Savage – with The Dallas Morning News April 9, 2010.

Research Spotlight: Breaking the human speed limit

SMU sprinter Ebony CuingtonJamaican sprinter Usain Bolt‘s record-setting performances have unleashed a wave of interest in the ultimate limits to human running speed. A new study published Jan. 21, 2010, in the Journal of Applied Physiology offers intriguing insights into the biology and perhaps even the future of human running speed.

The newly published evidence identifies the critical variable imposing the biological limit to running speed, and offers an enticing view of how the biological limits might be pushed back beyond the nearly 28 miles per hour speeds achieved by Bolt to speeds of perhaps 35 or even 40 miles per hour.

The new paper, “The biological limits to running speed are imposed from the ground up,” was authored by Peter Weyand of SMU; Rosalind Sandell and Danille Prime, both formerly of Rice University; and Matthew Bundle of the University of Wyoming.

“The prevailing view that speed is limited by the force with which the limbs can strike the running surface is an eminently reasonable one,” says Weyand, associate professor of applied physiology and biomechanics in the Annette Caldwell Simmons School of Education and Human Development.

“If one considers that elite sprinters can apply peak forces of 800 to 1,000 pounds with a single limb during each sprinting step, it’s easy to believe that runners are probably operating at or near the force limits of their muscles and limbs,” he says. “However, our new data clearly show that this is not the case. Despite how large the running forces can be, we found that the limbs are capable of applying much greater ground forces than those present during top-speed forward running.”

The researchers found that the critical biological limit is actually imposed by time – specifically, the very brief periods of time available to apply force to the ground while sprinting. In elite sprinters, foot-ground contact times are less than one-tenth of one second, and peak ground forces occur within less than one-twentieth of one second of the first instant of foot-ground contact.

The researchers used a high-speed treadmill capable of attaining speeds greater than 40 miles per hour and of acquiring precise measurements of the forces applied to the surface with each footfall. They also had subjects perform at high speeds in different gaits. In addition to completing traditional top-speed forward running tests, subjects hopped on one leg and ran backward to their fastest possible speeds on the treadmill.

The unconventional tests were selected to examine the prevailing belief that human running speed is limited by how forcefully a runner’s limbs can strike the ground. However, the researchers found that the ground forces applied while hopping on one leg at top speed exceeded those applied during top-speed forward running by 30 percent or more, and that the forces generated by the active muscles within the limb were roughly 1.5 to 2 times greater in the one-legged hopping gait.

The new work shows that running speed limits are set by the contractile speed limits of the muscle fibers themselves, with fiber contractile speeds setting the limit on how quickly the runner’s limb can apply force to the running surface, the researchers say.

Read more and review international press coverage at the SMU Research blog

(Above, sophomore sprinter Ebony Cuington of SMU’s track and field team.)

Research Spotlight: Prosthetic legs gave sprinter advantage

Peter Weyand and Oscar PistoriusThe artificial lower limbs of double-amputee Olympic hopeful Oscar Pistorius give him a clear and major advantage over his competition, taking 10 seconds or more off what his 400-meter race time would be if his prosthesis behaved like intact limbs.

That’s the conclusion – released to the public for the first time – of human performance experts Peter Weyand of SMU and Matthew Bundle of the University of Wyoming.

The Weyand-Bundle conclusion is part of a written point-counterpoint style debate published online Nov. 19 in the Journal of Applied Physiology. Weyand and Bundle were the first two authors of the study publishing the test results acquired as part of the legal appeal process undertaken after the governing body of track and field – the International Association of Athletics Federations (IAAF) – banned Pistorius from able-bodied track competitions, including the Olympics.

In banning Pistorius, the IAAF had concluded on the basis of other data that Pistorius’ J-shaped artificial lower limbs, called “Cheetahs” by the manufacturer, gave him a competitive advantage over able-bodied competitors. But the ban subsequently was overturned on appeal to the Court of Arbitration for Sport (CAS) in Lausanne, Switzerland.

The case has been considered groundbreaking for the eligibility of disabled athletes and the regulation of prosthetic technology in sport. Pistorius hopes to qualify for the 2012 Olympics.

The newly released conclusion from Weyand and Bundle analyzes the scientific evidence and quantifies the competitive advantage provided by Pistorius’ “Cheetah” limbs.

“Pistorius’ sprinting mechanics are anomalous, advantageous and directly attributable to how much lighter and springier his artificial limbs are. The blades enhance sprint running speeds by 15-30 percent,” says Weyand, associate professor of applied physiology and biomechanics in SMU’s Annette Caldwell Simmons School of Education and Human Development. Below the knee, Pistorius’ limbs weigh less than half as much as the limbs of an able-bodied male sprinter.

(Above, SMU Professor Peter Weyand and sprinter Oscar Pistorius during testing. Photo by Jeff Fitlow, Rice University.)

Read more from the SMU Research blog

Research Spotlight: Animal athleticism

Mouse lifts elephantIf 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.

Peter Weyand in the news:

TIME Magazine: How Fast Can Humans Go?
The Times of India: Diet not a factor in sprinter’s speed

Faculty in the News: Summer 2008

VOTE buttonsCal Jillson, Political Science, provided expertise for several Election 2008 stories during the summer, discussing:

  • the significance of Hillary Clinton’s prime-time speech placement at the Democratic National Convention in The Canadian Press Aug. 24, 2008
  • the drama viewers won’t see at the major parties’ political conventions in The Arizona Republic Aug. 18, 2008
  • the “mixed bag” for students and universities resulting from the new Higher Education Act in The Fort Worth Star-Telegram Aug. 10, 2008, as well as Texas’ fund-raising importance to both major political parties in the paper’s July 28, 2008 edition
  • the reasons why John Cornyn’s campaign press releases are aimed at his Republican colleagues in the U.S. Senate rather than at his Democratic opponent, Rick Noriega, in The Houston Chronicle Aug. 4, 2008
  • Texas Democrats’ hopes that Barack Obama’s candidacy can help the state party rebound in the Associated Press July 17, 2008, as well as the lack of a “quick fix” for the foreclosure crisis, now matter who is elected president, with the wire service for its July 5, 2008 edition
  • how the gay-marriage issue will play out in the presidential campaign in Reuters June 19, 2008
  • the differences in style and substance between Cindy McCain and Michelle Obama in Singapore’s The Electric New Paper June 15, 2008

Gas pumpBruce Bullock, Maguire Energy Institute, spoke with several media outlets during Summer 2008 about soaring fuel prices and other energy issues, including:

Peter Weyand, Simmons School of Education and Human Development, discussed Usain Bolt’s Olympic sprinting performance, and the possibility of humans someday running as fast as the fastest four-legged animals, with The Times of India Aug. 20, 2008.

Suku Nair, Computer Science and Engineering, talked about growing concerns for the security of wireless technology with Fox 4 News Aug. 17, 2008.

SMU Olympic swimmerDave Wollman, Track and Field/Cross Country, shared tips on how to train like an Olympian with The Dallas Morning News Aug. 12, 2008.

Fred Moss, Law, discussed recent developments in the Dallas City Hall corruption case with CBS 11 News Aug. 13, 2008. He talked about the merits of hate-crime charges being filed against a man accused of committing random shootings in four Dallas suburbs with The Dallas Morning News July 9, 2008. In addition, he discussed the issues involved in using DNA testing to exonerate those who may have been wrongly convicted of crimes with Reuters July 2, 2008.

Van Kemper, Anthropology, spoke with The Dallas Morning News Aug. 12, 2008, about how the proposed renaming of historic Ross Avenue has put the Dallas City Council in a no-win situation.

Mike Davis, Finance, discussed why the Consumer Price Index may not match a family’s reality with The Dallas Morning News Aug. 4, 2008.

Linda Eads, Law, talked about the merits of searching a defense attorney’s office in a Frisco, Texas murder-for-hire case with The Dallas Morning News July 27, 2008.

Edward Fox, Marketing, discussed the implications of the Minyard supermarket chain’s sale of 37 Carnival stores, along with the Carnival brand itself, with The Dallas Morning News July 24, 2008. He also talked about Wal-Mart’s plans to dramatically scale down a proposed new store in Austin with The Austin American-Statesman June 24, 2008.

Planet EarthMaria Richards, Earth Sciences, discussed geothermal energy as the “lost” component of the alternative-energy push with U.S. News & World Report July 21, 2008.

Patricia Mathes, Institute for Reading Research, talked about North Texas students’ struggles with the written portion of the TAKS test with The Dallas Morning News July 20, 2008.

Mark Chancey, Religious Studies, discussed a decision by the State Board of Education to allow elective Bible courses in Texas high schools with The Dallas Morning News July 11, 2008.

Matt Wilson, Political Science, discussed whether Karl Rove’s criticism of Mitt Romney is aimed at helping Romney become John McCain’s running mate with Salt Lake City’s Deseret News July 16, 2008. He also talked about why both Barack Obama and John McCain need the abortion issue with Reuters May 28, 2008.

Al Armendariz, Environmental and Civil Engineering, discussed the shortcomings of the new North Texas clean-air plan with the Dallas Business Journal July 11, 2008.

Geoff Orsak, Engineering Dean, provided expertise for a Robert Miller column on how North Texas engineering schools are meeting the demand for engineers with state-of-the-art programs and facilities. The column appeared in The Dallas Morning News June 29, 2008.

Alan Brown, Psychology, discussed his research, which may reveal the secret to winning game shows, with Psychology Today for its July/August 2008 issue.

Dan Howard, Marketing, provided expertise for a story on how frugal spenders can buck an economic downturn that appeared in The Arizona Republic Aug. 8, 2008. He talked about how rising ticket prices will affect the future of the airline industry in The Dallas Morning News June 23, 2008. In addition, he discussed how General Motors’ possible discontinuation of the Hummer reflects the restructuring of the North American automotive industry with The Ottawa Citizen June 14, 2008.

Jessica Dixon, Law, discussed the “puzzling” actions of Texas Child Protective Services in the case of the FDLS polygamist cult with The Dallas Morning News June 18, 2008.

Oil derrickFrank Lloyd, Cox Executive Education, discussed the importance of capable leadership in the global petroleum industry with The Earth Times June 18, 2008.

Robin Lovin, Maguire University Professor of Ethics, discussed the changing relationship between religion and politics in an essay published in Religion and Ethics Newsweekly June 12, 2008.

Joseph Dancy, Law, discussed how landowners can test the mineral-rights market through an eBay auction with Platts June 3, 2008

Ron Moss, Admissions, discussed the effects of intense college admission competition among the 2008 high school graduating class with WFAA Channel 8 June 3, 2008.