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GAINcast Episode 89: How Speed Happens (with Peter Weyand)

“People recognize the power of science, in terms of testing and numbers. But unless you’re involved in it it’s hard to appreciate the creativity that is also part of the process.” — Peter Weyand

The founder of modern sports performance training, Vern Gambetta, interviewed SMU locomotion researcher Peter Weyand about human speed and performance for his GAINcast show.

The GAINcast name is an acronym for the internationally recognized Gambetta’s self-made sports performance education, outreach and training efforts, Gambetta Athletic Improvement Network.

Gambetta’s 60-minute interview with Weyand posted Nov. 2, 2017, “Gaincast Episode 89: How Speed Happens (with Peter Weyand).”

In it, Weyand touches on the experiences early in his career as a high school and college athlete playing basketball and running track that sparked his pursuit of a research and academic career in sports science and human performance.

As a high school coach, Weyand’s early interest intensified, leading him to pursue advanced degrees and a scientific career exploring the mechanics of human locomotion and speed, including at the University of Georgia and then at Harvard’s Concord Field Station.

During that time, Weyand worked with early pioneers in the biomechanics and human performance field, including renowned researcher Dick Taylor. At the field station in particular, Weyand credits Taylor with mentoring young researchers in aggressively and fearlessly digging into basic science questions surrounding mammalian locomotion.

“It was wide open, anything goes. It wasn’t these reductionist questions …. It was anything under the sun you could cook up. And there was an insistence on good scientific questions, and a real integrative perspective on all of it. Those were my formative scientific experiences. People recognize the power of science, in terms of testing and numbers. But unless you’re involved in it it’s hard to appreciate the creativity that is also part of the process. There’s an art of doing science and Dick was a master of that. And everybody that came through that field station under his training, which is really a who’s who in our field in many respects, learned that art from him.”

Weyand is an expert on human locomotion and the mechanics of running. Research from his SMU Locomotor Performance Laboratory in SMU’s Annette Caldwell Simmons School of Education and Human Development has produced ground-breaking scientific findings about the science of human speed.

The lab focuses on the mechanical basis of human performance and includes physicist and engineer Laurence Ryan, an expert in force and motion analysis.

The Weyand lab’s most recent research found that the world’s fastest sprinter, Usain Bolt, has an asymmetrical running gait, contrary to the common notions about coaching and training for speed. Bolt’s asymmetry was discovered using the lab’s two-mass model tool, which the researchers have described in the Journal of Experimental Biology, “A general relationship links gait mechanics and running ground reaction forces.” The model can assess the crucial early portion of foot-ground contact — the impact-phase force and time relationships — from motion data only.

Weyand is Glenn Simmons Professor of Applied Physiology and professor of biomechanics in the Department of Applied Physiology & Wellness.

Listen to the podcast.

EXCERPT:

By Martin Bingisser
GAINcast

There are some basic questions out there that are difficult to answer, such as what limits human running speed. As technology advances, scientists can better study and start to answer this and other simple questions like what makes one athlete faster than another.

Dr. Peter Weyand has spent decades researching locomotion on both animals and humans. His work with elite sprinters has brought some interesting conclusions and is driving the field forward. On this episode of the GAINcast he joins us to discuss his research and its practical implications.

Listen to the podcast.

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The New York Times: Something Strange in Usain Bolt’s Stride

Bolt is the fastest sprinter ever in spite of — or because of? — an uneven stride that upends conventional wisdom.

The New York Times reporter Jeré Longman covered the research of SMU biomechanics expert Peter Weyand and his colleagues Andrew Udofa and Laurence Ryan for a story about Usain Bolt’s apparent asymmetrical running stride.

The article, “Something Strange in Usain Bolt’s Stride,” published July 20, 2017.

The researchers in the SMU Locomotor Performance Laboratory reported in June that world champion sprinter Usain Bolt may have an asymmetrical running gait. While not noticeable to the naked eye, Bolt’s potential asymmetry emerged after the researchers dissected race video to assess his pattern of ground-force application — literally how hard and fast each foot hits the ground. To do so they measured the “impulse” for each foot.

Biomechanics researcher Udofa presented the findings at the 35th International Conference on Biomechanics in Sport in Cologne, Germany. His presentation, “Ground Reaction Forces During Competitive Track Events: A Motion Based Assessment Method,” was delivered June 18.

The analysis thus far suggests that Bolt’s mechanics may vary between his left leg to his right. The existence of an unexpected and potentially significant asymmetry in the fastest human runner ever would help scientists better understand the basis of maximal running speeds. Running experts generally assume asymmetry impairs performance and slows runners down.

Udofa has said the observations raise the immediate scientific question of whether a lack of symmetry represents a personal mechanical optimization that makes Bolt the fastest sprinter ever or exists for reasons yet to be identified.

Weyand, who is Glenn Simmons Professor of Applied Physiology and professor of biomechanics in the Department of Applied Physiology & Wellness in SMU’s Annette Caldwell Simmons School of Education & Human Development, is director of the Locomotor Lab.

An expert on human locomotion and the mechanics of running, Weyand has been widely interviewed about the running controversy surrounding double-amputee South African sprinter Oscar Pistorius. Weyand co-led a team of scientists who are experts in biomechanics and physiology in conducting experiments on Pistorius and the mechanics of his racing ability.

For his most recently published research, Weyand was part of a team that developed a concise approach to understanding the mechanics of human running. The 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.

They described the two-mass model earlier this year in the Journal of Experimental Biology in their article, “A general relationship links gait mechanics and running ground reaction forces.” It’s available at bitly, http://bit.ly/2jKUCSq.

The New York Times subscribers or readers with remaining limited free access can read the full story.

EXCERPT:

By Jeré Longman
The New York Times
DALLAS — Usain Bolt of Jamaica appeared on a video screen in a white singlet and black tights, sprinting in slow motion through the final half of a 100-meter race. Each stride covered nine feet, his upper body moving up and down almost imperceptibly, his feet striking the track and rising so rapidly that his heels did not touch the ground.

Bolt is the fastest sprinter in history, the world-record holder at 100 and 200 meters and the only person to win both events at three Olympics. Yet as he approaches his 31st birthday and retirement this summer, scientists are still trying to fully understand how Bolt achieved his unprecedented speed.

Last month, researchers here at Southern Methodist University, among the leading experts on the biomechanics of sprinting, said they found something unexpected during video examination of Bolt’s stride: His right leg appears to strike the track with about 13 percent more peak force than his left leg. And with each stride, his left leg remains on the ground about 14 percent longer than his right leg.

This runs counter to conventional wisdom, based on limited science, that an uneven stride tends to slow a runner down.

So the research team at S.M.U.’s Locomotor Performance Laboratory is considering a number of questions as Bolt prepares for what he said would be his final performances at a major international competition — the 100 meters and 4×100-meter relay next month at the world track and field championships in London.

Among those questions: Does evenness of stride matter for speed? Did Bolt optimize this irregularity to become the fastest human? Or, with a more balanced stride during his prime, could he have run even faster than 9.58 seconds at 100 meters and 19.19 seconds at 200 meters?

“That’s the million-dollar question,” said Peter Weyand, director of the S.M.U. lab.

The S.M.U. study of Bolt, led by Andrew Udofa, a doctoral researcher, is not yet complete. And the effect of asymmetrical strides on speed is still not well understood. But rather than being detrimental for Bolt, the consequences of an uneven stride may actually be beneficial, Weyand said.

It could be that Bolt has naturally settled into his stride to accommodate the effects of scoliosis. The condition curved his spine to the right and made his right leg half an inch shorter than his left, according to his autobiography.

Initial findings from the study were presented last month at an international conference on biomechanics in Cologne, Germany. Most elite sprinters have relatively even strides, but not all. The extent of Bolt’s variability appears to be unusual, Weyand said.

“Our working idea is that he’s probably optimized his speed, and that asymmetry reflects that,” Weyand said. “In other words, correcting his asymmetry would not speed him up and might even slow him down. If he were to run symmetrically, it could be an unnatural gait for him.”

Antti Mero, an exercise physiologist at the University of Jyvaskyla in Finland, who has researched Bolt’s fastest races, said he was intrigued by the S.M.U. findings.

The New York Times subscribers or readers with remaining limited free access can read the full story.

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Does symmetry matter for speed? Study finds Usain Bolt may have asymmetrical running gait

A new method for assessing patterns of ground-force application suggests the right and left legs of the world’s fastest man may perform differently, defying current scientific assumptions about running speed.

World champion sprinter Usain Bolt may have an asymmetrical running gait, according to data recently presented by researchers from Southern Methodist University, Dallas.

While not noticeable to the naked eye, Bolt’s potential asymmetry emerged after SMU researchers assessed the running mechanics of the world’s fastest man.

The analysis thus far suggests that Bolt’s mechanics may vary between his left leg and his right, said Andrew Udofa, a biomechanics researcher in the SMU Locomotor Performance Laboratory.

The existence of an unexpected and potentially significant asymmetry in the fastest human runner ever would help scientists better understand the basis of maximal running speeds. Running experts generally assume asymmetry impairs performance and slows runners down.

“Our observations raise the immediate scientific question of whether a lack of symmetry represents a personal mechanical optimization that makes Bolt the fastest sprinter ever or exists for reasons yet to be identified,” said Udofa, a member of the research team.

The SMU Locomotor Lab, led by Peter Weyand, focuses on the mechanical basis of human performance. The group includes physicist and engineer Laurence Ryan, an expert in force and motion analysis, and doctoral researcher Udofa.

The intriguing possibility of Bolt’s asymmetry emerged after the SMU researchers decided to assess his pattern of ground-force application — literally how hard and fast each foot hits the ground. To do so they measured the “impulse” for each foot.

Impulse is a combination of the amount of force applied to the ground multiplied by the time of foot-ground contact.

“The manner in which Bolt achieves his impulses seems to vary from leg to leg,” Udofa said. “Both the timing and magnitude of force application differed between legs in the steps we have analyzed so far.”

Impulse matters because that’s what determines a runner’s time in the air between steps.

“If a runner has a smaller impulse, they don’t get as much aerial time,” Weyand said. “Our previous published research has shown greater ground forces delivered in shorter periods of foot-ground contact are necessary to achieve faster speeds. This is true in part because aerial times do not differ between fast and slow runners at their top speeds. Consequently, the combination of greater ground forces and shorter contact times is characteristic of the world’s fastest sprinters.”

The researchers didn’t test Bolt in the SMU lab. Instead, they used a new motion-based method to assess the patterns of ground-force application. They analyzed Bolt and other elite runners using existing high-speed race footage available from NBC Universal Sports. The runners were competing in the 2011 Diamond League race at the World Athletics Championships in Monaco.

Udofa analyzed 20 of Bolt’s steps from the Monaco race, averaging data from 10 left and 10 right.

The researchers relied upon foot-ground contact time, aerial time, running velocity and body mass to determine the ground reaction forces using the new method, made possible by the “two-mass model” of running mechanics.

Runners typically run on a force-instrumented treadmill or force plates for research examining running ground-reaction forces. However, the two-mass model method provides a tool that enables motion-based assessments of ground reaction forces without direct force measurements.

“There are new avenues of research the model may make possible because direct-force measurements are not required,” Weyand said. “These include investigations of the importance of symmetry for sprinting performance. The two-mass model may facilitate the acquisition of data from outside the lab to help us better address these kinds of questions.”

Udofa presented the findings at the 35th International Conference on Biomechanics in Sport in Cologne, Germany. His presentation, “Ground Reaction Forces During Competitive Track Events: A Motion Based Assessment Method,” was delivered June 18.

Two-mass model relies on basic motion data
SMU researchers developed the concise two-mass model as a simplified way to predict the entire pattern of force on the ground — from impact to toe-off — with very basic motion data.

The model integrates classic physics and human anatomy to link the motion of individual runners to their patterns of force on the ground.

It provides accurate predictions of the ground force vs. time patterns throughout each instant of the contact period, regardless of limb mechanics, foot-strike type or running speed.

The two-mass model is substantially less complex than other scientific models that explain patterns of ground force application during running. Most existing models are more elaborate in relying on 14 or more variables, many of which are less clearly linked to the human body.

“The two-mass model provides us with a new tool for assessing the crucial early portion of foot-ground contact that is so important for sprinting performance,” said Udofa. “The model advances our ability to assess the impact-phase force and time relationships from motion data only.”

The two-mass model was developed in SMU’s Locomotor Performance Laboratory by Kenneth P. Clark, now an assistant professor in the Department of Kinesiology at West Chester University, West Chester, Pa.; Ryan, a physicist and research engineer at SMU’s Locomotor Performance Laboratory; and Weyand.

The researchers described the two-mass model earlier this year in the Journal of Experimental Biology in their article, “A general relationship links gait mechanics and running ground reaction forces.” It’s available at bitly, http://bit.ly/2jKUCSq.

Support for the research came from the U.S. Army Medical Research and Materiel Command.

Weyand is Glenn Simmons Professor of Applied Physiology and professor of biomechanics in the Department of Applied Physiology & Wellness in SMU’s Annette Caldwell Simmons School of Education & Human Development. — Margaret Allen, SMU

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GotScience.org: Can You Improve Your Running with Physics?

The researchers studied the running mechanics of forty-two people ranging from recreational runners to Olympic medalists.

GotScience.org reporter Emily Rhode covered the research of SMU biomechanics expert Peter Weyand and the SMU Locomotor Laboratory. Weyand is the director of the Locomotor Lab.

Other authors on the study were Laurence Ryan, a physicist and research engineer in the lab, and
Kenneth Clark , previously with the lab and now an assistant professor in the Department of Kinesiology at West Chester University in West Chester, Penn.

The three have developed a concise approach to understanding the mechanics of human running. The 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 GotScience.org article, “Can You Improve Your Running with Physics?,” published March 27, 2017.

Weyand is Glenn Simmons Professor of Applied Physiology and professor of biomechanics in the Department of Applied Physiology and Wellness in SMU’s Annette Caldwell Simmons School of Education and Human Development.

An expert on human locomotion and the mechanics of running, Weyand has been widely interviewed about the controversy surrounding double-amputee South African sprinter Oscar Pistorius. Controversy has swirled around the sprinter over whether his light-weight, carbon-fiber prosthetic “Cheetah” legs give him a competitive advantage.

Weyand helped lead a team of scientists who are experts in biomechanics and physiology in conducting experiments on Pistorius and the mechanics of his racing ability.

Read the full story.

EXCERPT:

By Emily Rhode
Gotscience.org
Running is one of the simplest forms of exercise we can do. It requires no protective gear or fancy equipment. At its core, it just requires force. Runners are constantly searching for clues for how to improve their speed and prevent injury. But until now, there was no easy way to fully assess the way a runner moves. In a new study published in the Journal of Experimental Biology, researchers at Southern Methodist University describe a new method that requires nothing more than a quality camera and basic laws of physics to predict how a runner and the ground will impact each other.

Newton’s second law of motion says that force is mass multiplied by acceleration. A runner’s mechanics, or movement, can be represented by a simple waveform—a visual representation of force over time. The moment the runner’s foot hits the ground is represented by the beginning of the wave. As the mass of the runner’s body accelerates toward the ground, the amount of force increases and the wave climbs. The wave then slopes down as the runner begins the motion of lifting the leg again.

Collecting the data to create this pattern of force between the runner’s body and the ground is normally a complicated process that requires knowing the masses and motion of as many as fourteen different variables. A team consisting of Dr. Kenneth P. Clark, Dr. Laurence J. Ryan, and Dr. Peter G. Weyand believed that they could simplify the process considerably by focusing on just two parts of the body: the lower leg and the foot.

The researchers studied the running mechanics of forty-two people ranging from recreational runners to Olympic medalists. They measured each person’s body mass and used high-speed cameras to capture the motion of running. At the same time, a specialized treadmill recorded the force of the runners’ footfalls as they moved through their strides. The team then compared the real data to an algorithm, or set of mathematical steps, that they developed to predict an individual’s waveform pattern.

Read the full story.

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Huffington Post: A New Physics Discovery Could Make You A Faster Runner

It’s all about the force

Reporter Sarah DiGiullo with the online news magazine The Huffington Post covered the research of Peter Weyand and the SMU Locomotor Laboratory. Weyand, who is Glenn Simmons Professor of Applied Physiology and professor of biomechanics in the Department of Applied Physiology and Wellness in SMU’s Annette Caldwell Simmons School of Education and Human Development, is the director of the Locomotor Lab.

Other authors on the study were Laurence Ryan, a physicist and research engineer in the lab, and
Kenneth Clark , previously with the lab and now an assistant professor in the Department of Kinesiology at West Chester University in West Chester, Penn.

The three have developed a concise approach to understanding the mechanics of human running. The 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 Huffington Post article, “Researchers reveal the mechanics of running is simpler than thought – and it could revolutionize shoe design,” published Feb. 13, 2017.

Read the full story.

EXCERPT:

By Sarah DiGiullo
The Huffington Post
When it comes to race day, runners may have favorite moisture-wicking gear, a stopwatch and tunes to help get that coveted personal record.

But physicists say running at your top speed may actually be a lot simpler. It all comes down to the force of your foot striking the ground ― and that’s about it.

After studying the physics behind some of the world’s fastest runners, researchers came up with a new model they say could make anyone faster. It may help injured runners recover faster, too.

The researchers developed an equation that calculates two forces: The total force of the shin, ankle and foot striking the ground, and the total force of the rest of the body striking the ground. The method, which they detailed in an article published recently in the Journal of Experimental Biology, can predict how fast an athlete will run.

“We’ve known for quite some time that fast people are fast because they’re able to hit the ground harder in relation to how much they weigh,” explained the study’s co-author, Peter Weyand, director of the Locomotor Performance Laboratory at Southern Methodist University in Dallas.

But Weyand and his team were looking to better understand why it was that some people are able to hit the ground harder than others. The new equation makes the answer a lot clearer, with fewer measurements than previous models.

Read the full story.