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1st proton collisions at the world’s largest science experiment expected to start the first or second week of June

“No significant signs of new physics with the present data yet but it takes only one significant deviation in the data to change everything.” — Albert De Roeck, CERN

First collisions of protons at the world’s largest science experiment are expected to start the first or second week of June, according to a senior research scientist with CERN’s Large Hadron Collider in Geneva.

“It will be about another six weeks to commission the machine, and many things can still happen on the way,” said physicist Albert De Roeck, a staff member at CERN and a professor at the University of Antwerp, Belgium and UC Davis, California. De Roeck is a leading scientist on CMS, one of the Large Hadron Collider’s key experiments.

The LHC in early April was restarted for its second three-year run after a two-year pause to upgrade the machine to operate at higher energies. At higher energy, physicists worldwide expect to see new discoveries about the laws that govern our natural universe.

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De Roeck made the comments Monday while speaking during an international meeting of more than 250 physicists from 30 countries on the campus of Southern Methodist University, Dallas.

“There are no significant signs of new physics yet,” De Roeck said of the data from the first run, adding however that especially SUSY diehards — physicists who predict the existence of a unique new theory of space and time called SuperSymmetry — maintain hopes of seeing evidence soon of that theory.

De Roeck in fact has high expectations for the possibility of new discoveries that could change the current accepted theory of physical reality, the Standard Model.

“It will take only one significant deviation in the data to change everything,” De Roeck said. “The upgraded machine works. Now we have to get to the real operation for physics.”

“Unidentified Lying Object” not a problem — remains stable
But work remains to be done. One issue the accelerator physicists remain cautiously aware of, he said, is an “Unidentified Lying Object” in the beam pipe of the LHC’s 17-mile underground tunnel, a vacuum tube where proton beams collide and scatter particles that scientists then analyze for keys to unlock the mysteries of the Big Bang and the cosmos.

Because the proton beam is sensitive to the geometry of the environment and can be easily blocked, the beam pipe must be free of even the tiniest amount of debris. Even something as large as a nitrogen particle could disrupt the beam. Because the beam pipe is a sealed vacuum it’s impossible to know what the “object” is.

“The unidentified lying object turns out not to be a problem for the operation, it’s just something to keep an eye on,” De Roeck said. “It’s in the vacuum tube and it’s not a problem if it doesn’t move and remains stable.”

The world’s largest particle accelerator, the Large Hadron Collider made headlines when its global collaboration of thousands of scientists in 2012 observed a new fundamental particle, the Higgs boson. After that, the collider was paused for the extensive upgrade. Much more powerful than before, as part of Run 2 physicists on the Large Hadron Collider’s experiments are analyzing new proton collision data to unravel the structure of the Higgs.

The Large Hadron Collider straddles the border between France and Switzerland. Its first run began in 2009, led by CERN, the European Organization for Nuclear Research, in Geneva, through an international consortium of thousands of scientists.

Particle discoveries unlock mysteries of cosmos, pave way for new technology
The workshop in Dallas, the “2015 International Workshop on Deep-Inelastic Scattering,” draws the world’s leading scientists each year to an international city for nuts and bolts talks that drive the world’s leading-edge physics experiments, such as the Large Hadron Collider.

Going into the second run, De Roeck said physicists will continue to look for anomalies, unexpected decay modes or couplings, multi-Higgs production, or larger decay rates than expected, among other things.

Particle discoveries by physicists resolve mysteries, such as questions surrounding Dark Matter and Dark Energy, and the earliest moments of the Big Bang. But particle discoveries also are ultimately applied to other fields to improve everyday life, such as medical technologies like MRIs and PET scans, which diagnose and treat cancer.

For example, proton therapy is the newest non-invasive, precision scalpel in the fight against cancer, with new centers opening all over the world.

Hosted by the SMU Department of Physics in Dedman College, the Dallas meeting of physicists began Monday, April 27, 2015, and runs through Friday, May 1, 2015.

The workshop is sponsored by SMU, U.S. Department of Energy’s Office of Science, CERN, National Science Foundation, Fermi National Accelerator Laboratory, Brookhaven National Laboratory, DESY national research center and Thomas Jefferson National Accelerator Facility. — Margaret Allen

Follow SMUResearch.com on twitter at @smuresearch.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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SMU’s engineering students to test new virtual reality game to practice solving hands-on infrastructure failure problems

Games let people experience the unknown and unfamiliar in a virtual world, and have the power to engage their users.

SMU’s engineering students will help test a new virtual reality game that will someday be rolled out to classrooms everywhere to help students design, inspect and test geotechnical — soil and rock — systems virtually.

SMU will receive $80,000 in funding as part of a larger $650,000 grant from the National Science Foundation, which was awarded to professors at Rensselaer Polytechnic Institute, Troy, N.Y.

Called Geo Explorer, the game places students in a virtual field-testing experience to learn how to use the instrument and interpret its results, said Usama El Shamy, associate professor, department of civil and environmental engineering, SMU Lyle School of Engineering.

“Nowadays, Students get hands-on lab experiences testing element-level samples in geotechnical engineering classes,” said El Shamy. “When it comes to field testing, they only see images of the instrument and deal with raw test data.”

The game will broaden the learning experience considerably.

“The game is intended to place the students in a virtual environment where they can perform the field test, and gather and interpret its data as they play,” he said.

“Other modules of the game will place the student in the position of an engineer inspecting the integrity of a levee after a rain storm. The student should be able to promptly report any warning signs of potential failure of the levee,” El Shamy said. “Failure to do a timely report would result in failure of the levee, or, in other words, game over.”

Mixed-reality and mobile game virtually brings students into the field with immersive learning
Geo Explorer is a mixed-reality and mobile game to virtually bring students into the field to conduct geotechnical site investigations and evaluations. It’s being developed by Rensselaer civil engineering faculty Tarek Abdoun and Victoria Bennett.

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“Geo Explorer has a tremendous potential to teach students about the deadly consequences of deteriorating infrastructure,” Bennett said. “Games let people experience the unknown and unfamiliar in a virtual world, and have the power to engage their users.”

The immersive learning from playing Geo Explorer will let students participate in geotechnical field testing, inspect levees during and after extreme storms, assess stability and make decisions about future actions related to flood-control infrastructure.

El Shamy will test the use of the game in SMU’s undergraduate geotechnical engineering classes, which are part of the Lyle School’s civil engineering program, then provide feedback on the game’s design and impact on intended learning outcomes. Preliminary testing of the game in classes will start in April.

A bridge to the lab, Geo Explorer incorporates testing actual soil samples
Geo Explorer also includes a bridge to the actual laboratory. Players will not only use mobile devices, downloading field data, receiving messages from characters and collaborating with classmates, but will test actual soil samples in the lab and can upload results to the game.

Abdoun and Bennett note that natural disasters such as Hurricane Katrina illustrate the serious consequences of a deteriorating infrastructure and a public ill-equipped to respond to weather extremes.

Such challenges cannot be adequately met in the traditional classroom.

Games like Geo Explorer can address the gaps in geotechnical engineering education by providing realistic virtual experience with the unfamiliar, letting participants weigh choices and experience their consequences.

“Ultimately, Geo Explorer will be available for free and be scaled for use by students from kindergarten through high school, particularly in districts with a high percentage of minorities who are underrepresented in technical fields,” Abdoun said.

Concept opens up possibilities for developing games in other areas of science and technology
Geo Explorer is intended to educate the workforce in science, technology, engineering and math, said Rensselaer’s Shekhar Garde, dean of the School of Engineering.

“Geo Explorer has a great potential to educate students about grand challenges in infrastructure resilience, sustainability and stewardship,” Garde said. “It also opens up possibilities for developing games in other areas of science and technology for a range of applications in human health, including chemical and biological safety.”

Funds will be used to utilize the game in a geotechnical course that integrates Geo Explorer. The project builds on game modules developed by Deltares, an institute for applied research in water, subsurface and infrastructure based in the Netherlands.

Besides SMU and Rensselaer faculty, other partners include Casper Harteveld, Northeastern University; Flora McMartin, Broad-Based Knowledge; and Joseph Tront, Virginia Polytechnic Institute and State University; Manhattan College; and California State University Fullerton. — Southern Methodist University, Rensselaer Polytechnic

Follow SMUResearch.com on twitter at @smuresearch.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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17 million-year-old whale fossil provides 1st exact date for East Africa’s puzzling uplift

Uplift and aridification of East Africa causing changes in vegetation has been considered a driver of human evolution. Now a fossil whale stranded far inland in Kenya marks the first time scientists can pinpoint how many millions of years ago the uplift began.

Uplift associated with the Great Rift Valley of East Africa and the environmental changes it produced have puzzled scientists for decades. Timing and starting elevation have been poorly understood.

Now paleontologists have tapped a fossil from the most precisely dated beaked whale in the world to pinpoint for the first time a date when East Africa’s mysterious elevation began. The stranded whale is the only one ever found so far inland on the African continent.

The 17 million-year-old fossil is from the beaked Ziphiidae whale family. It was discovered 740 kilometers inland at a elevation of 620 meters in modern Kenya’s harsh desert region, said vertebrate paleontologist Louis L. Jacobs, Southern Methodist University, Dallas.

At the time the whale was alive, it would have been swimming far inland up a river with a low gradient ranging from 24 to 37 meters over more than 600 to 900 kilometers, said Jacobs, a co-author of the study.

A map of Africa and Kenya showing where a 17-million-year-old whale fossil was found far inland . (Wichura/PNAS)
A map of Africa and Kenya showing where a 17-million-year-old whale fossil was found far inland . (Wichura/PNAS)

The study, published in the Proceedings of the National Academy of Sciences, provides the first constraint on the start of uplift of East African terrain from near sea level.

“The whale was stranded up river at a time when east Africa was at sea level and was covered with forest and jungle,” Jacobs said. “As that part of the continent rose up, that caused the climate to become drier and drier. So over millions of years, forest gave way to grasslands. Primates evolved to adapt to grasslands and dry country. And that’s when — in human evolution — the primates started to walk upright.”

Identified as a Turkana ziphiid, the whale would have lived in the open ocean, like its modern beaked cousins. Ziphiids, still one of the ocean’s top predators, are the deepest diving air-breathing mammals alive, plunging to nearly 10,000 feet to feed, primarily on squid.

In contrast to most whale fossils, which have been discovered in marine rocks, Kenya’s beached whale was found in river deposits, known as fluvial sediments, said Jacobs, a professor in the Roy M. Huffington Department of Earth Sciences of SMU’s Dedman College of Humanities and Sciences.

The whale fossil bones were originally thought to be those of a turtle specimen, as was recorded in the fossil catalogue for the Harvard Loperot Expedition in 1964.
The whale fossil bones were originally thought to be those of a turtle specimen, as was recorded in the fossil catalogue for the Harvard Loperot Expedition in 1964. (Museum of Comparative Zoology, Harvard University.)
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The ancient large Anza River flowed in a southeastward direction to the Indian Ocean.

The whale, probably disoriented, swam into the river and could not change its course, continuing well inland.

“You don’t usually find whales so far inland,” Jacobs said. “Many of the known beaked whale fossils are dredged by fishermen from the bottom of the sea.”

Determining ancient land elevation is very difficult, but the whale provides one near sea level.

“It’s rare to get a paleo-elevation,” Jacobs said, noting only one other in East Africa, determined from a lava flow.

Beaked whale fossil surfaced after going missing for more than 30 years
The beaked whale fossil was discovered in 1964 by J.G. Mead in what is now the Turkana region of northwest Kenya.

Mead, an undergraduate student at Yale University at the time, made a career at the Smithsonian Institution, from which he recently retired. Over the years, the Kenya whale fossil went missing in storage. Jacobs, who was at one time head of the Division of Paleontology for the National Museums of Kenya, spent 30 years trying to locate the fossil. His effort paid off in 2011, when he rediscovered it at Harvard University and returned it to the National Museums of Kenya.

The fossil is only a small portion of the whale, which Mead originally estimated was 7 meters long during its life. Mead unearthed the beak portion of the skull, 2.6 feet long and 1.8 feet wide, specifically the maxillae and premaxillae, the bones that form the upper jaw and palate.

The researchers reported their findings in “A 17-My-old whale constrains onset of uplift and climate change in east Africa” online at the PNAS web site.

Modern cases of stranded whales have been recorded in the Thames River in London, swimming up a gradient of 2 meters over 70 kilometers; the Columbia River in Washington state, a gradient of 6 meters over 161 kilometers; the Sacramento River in California, a gradient of 4 meters over 133 kilometers; and the Amazon River in Brazil, a gradient of 1 meter over 1,000 kilometers.

Besides Jacobs, other authors from SMU are Andrew Lin, Michael J. Polcyn, Dale A. Winkler and Matthew Clemens.

From other institutions, authors are Henry Wichura and Manfred R. Strecker, University of Potsdam, and Fredrick K. Manthi, National Museums of Kenya.

Funding for the research came from SMU’s Institute for the Study of Earth and Man and the SMU Engaged Learning program. — Margaret Allen

Follow SMUResearch.com on twitter at @smuresearch.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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Jurassic climate of large swath of western U.S. was more complex than previously known

First detailed chemical analysis of ancient soil from the Morrison Formation — a massive source of significant dinosaur discoveries for more than 100 years— reveals there was an unexpected abrupt change from arid to wet environments during the Jurassic.

Morrison Formation, Wyoming, ancient soil, Jurassic, Myers, SMU

The climate 150 million years ago of a large swath of the western United States was more complex than previously known, according to new research from Southern Methodist University, Dallas.

It’s been held that the climate during the Jurassic was fairly dry in New Mexico, then gradually transitioned to a wetter climate northward to Montana.

But based on new evidence, the theory of a gradual transition from a dry climate to a wetter one during the Jurassic doesn’t tell the whole story, says SMU paleontologist Timothy S. Myers, lead author on the study.

Geochemical analysis of ancient soils, called paleosols, revealed an unexpected and mysterious abrupt transition from dry to wet even though some of the samples came from two nearby locales, Myers said.

Myers discovered the abrupt transition through geochemical analysis of more than 40 ancient soil samples.

SMU paleontologist Timothy S. Myers collected this plastic bag of paleosol matrix in the field. Myers performed chemical analysis of the ancient soil by grinding it to a powder that is then fused into a glass disc for elemental analysis. (Myers, SMU)
Paleosol matrix was collected in the field by SMU paleontologist Timothy S. Myers for chemical analysis of the ancient soil by grinding it to a powder, which was then fused into a glass disc for elemental analysis. (Myers, SMU)

He collected the samples from the Morrison Formation, a vast rock unit that has been a major source of significant dinosaur discoveries for more than 100 years.

The Morrison extends from New Mexico to Montana, sprawling across 13 states and Canada, formed from sediments deposited during the Jurassic.

Myers’ study is the first in the Morrison to significantly draw on quantitative data — the geochemistry of the rocks.

The abrupt transition, Myers says, isn’t readily explained.

“I don’t have a good explanation,” he said. “Normally when you see these dramatic differences in climate in areas that are close to one another it’s the result of a stark variation in topography. But in this case, there weren’t any big topographic features like a mountain range that divided these two localities in the Jurassic.”

Surprisingly, paleosols from the sample areas did not reveal marked differences until they were analyzed using geochemical weathering indices.

Ancient soil samples from the Jurassic in Wyoming indicate this area of the massive Morrison Formation surprisingly was more arid than its counterpart in New Mexico. (Credit: Myers, SMU)
Paleosol samples from the Jurassic in Wyoming indicate this area of the massive Morrison Formation surprisingly was more arid than its counterpart in New Mexico. (Credit: Myers, SMU)

“It’s sobering to think that by just looking at the paleosols superficially at these localities, they don’t appear incredibly different. We see the same types of ancient soils in both places,” Myers said. “So these are some fairly major climate differences that aren’t reflected in the basic ancient soil types. Yet this is what a lot of scientists, myself included, depend on for a first pass idea of paleoclimate in an area — certain types of soils form in drier environments, others in wetter, others in cooler, that sort of thing.”

That didn’t hold true for the current study.

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With the geochemical analysis, Myers estimated the mean average precipitation during the Jurassic for northern Montana was approximately 45 inches, 20 inches for northern Wyoming and 30 inches for New Mexico.

“This changes how we view the distribution of the types of environments in the Morrison,” Myers said. “Too many times we talk about the Morrison as though it was this monolithic unit sprinkled with patchy, but similar, variations. But it’s incredibly large. It spans almost 10 degrees of latitude. So it’s going to encompass a lot of different environments. Regions with broadly similar climates can have internal differences, even over short distances. That’s the take-home.”

Myers is a postdoctoral scholar in SMU’s Shuler Museum of Paleontology in the Roy M. Huffington Department of Earth Sciences, Dedman College.

He reported his findings, “Multiproxy approach reveals evidence of highly variable paleoprecipitation in the Upper Jurassic Morrison Formation (western United States),” in The Geological Society of America Bulletin.

Co-authors of the study were Neil J. Tabor, SMU earth sciences professor and an expert in ancient soil, and Nicholas Rosenau, a stable isotope geochemist, Dolan Integration Group.

The popular artistic representations we see today of dinosaurs in a landscape setting are based on bits of evidence from plant and animal fossils found in various places, Tabor said. While that’s based on the best information to date, it’s probably inaccurate, he said. Myers’ findings provide new insights to many studies that have been done prior to his. This will drive paleontologists and geologists to seek out more quantitative data about the ancient environment.

“The geology of the Morrison has been studied exhaustively from an observational standpoint for 100 years,” Tabor said. “I have no doubt there will be many more fossil discoveries in the Morrison, even though over the past century we’ve gained a pretty clear understanding of the plants and animals at that time. But now we can ask deeper questions about the landscape and how organisms in the ancient world interacted with their environment.”

Surprising results: Northern locale more arid than southern locale
The Morrison Formation has produced some of our most familiar dinosaurs, as well as new species never seen before. Discoveries began in the late 1800s and ultimately precipitated the Bone Wars — the fossil equivalent of California’s Gold Rush.

After Myers studied dinosaur fossils from the Morrison, he became curious about the climate. Embarking on the geochemical analysis, Myers, like scientists before him, hypothesized the climate would be similar to modern zonal circulation patterns, which are driven by the distribution of the continents. Under that hypothesis, New Mexico would be relatively arid, and Wyoming and Montana both would be wetter at the time dinosaurs roamed the landscape.

Myers analyzed 22 paleosol samples from northern New Mexico, 15 from northern Wyoming and seven from southern Montana. The samples from Montana were younger than those from New Mexico, but roughly contemporary with the samples from Wyoming.

“We found that, indeed, New Mexico was relatively arid,” Myers said. “But the surprising part was that the Wyoming locality was more arid and had less rainfall than New Mexico, even though it was at a higher latitude, and above the mid-latitude arid belt. And the Montana locality, which is not far from the Wyoming locality, had the highest rainfall of all three. And there’s a very abrupt transition between the two.”

During the Jurassic, the Morrison was between 30 degrees north and 45 degrees north, which is about five degrees south of where it sits now. Its sediments were deposited from 155 to 148 million years ago. Some areas show evidence of a marine environment, but most were continental. The mean average precipitation determined for the Jurassic doesn’t match our modern distribution, Myers said.

Study underscores that understanding climate requires multiple approaches
Previously scientists speculated on the climate based on qualitative measures, such as types of soils or rocks, or types of sedimentary structures, and inferred climate from that.

“I tried to find quantitative information, but no one had done it,” Myers said. “There are entire volumes about Morrison paleoclimate, but not a single paper with quantitative estimates. Given the volume of important fossils that have come out of the Morrison, and how significant this formation is, it just struck me as important that it be done.”

Myers classified the fossil soils according to the Mack paleosol classification, and established the elemental composition of each one to determine how much weathering the paleosols had undergone.

“There are some elements, such as aluminum, that are not easily weathered out of soils,” Myers said. “There are others that are easily flushed out. We looked at the ratio of the elements, such as aluminum versus elements easily weathered. From that, we used the ratios to determine how weathered or not the soil was.”

These findings suggest that scientists must use different approaches to quantify paleoclimate, he said.

“It’s not enough to just look at soil types and draw conclusions about the paleoclimate,” Myers said. “It’s not even enough to look at rainfall in this quantitative fashion. There are numerous factors to consider.”

Funding for the study was provided by SMU Dedman College’s Roy M. Huffington Department of Earth Sciences, SMU’s Institute for the Study of Earth and Man, The Jurassic Foundation, Western Interior Paleontological Society, The Paleontological Society and The Geological Society of America. — Margaret Allen

Follow SMUResearch.com on twitter at @smuresearch.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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Key to speed? Elite sprinters are unlike other athletes — deliver forceful punch to ground

New research finds that world-class sprinters attack the ground to maximize impact forces and speed

The world’s fastest sprinters have unique gait features that account for their ability to achieve fast speeds, according to two new studies from Southern Methodist University, Dallas.

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 and lead author on the studies Ken Clark, a researcher in the SMU Locomotor Performance Laboratory. “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 SMU 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 researchers reported their findings with co-author and physicist Laurence J. Ryan, research engineer for the SMU Locomotor Performance Laboratory in the Annette Caldwell Simmons School of Education & Human Development.

The finding that elite sprinters apply greater ground forces with a distinctive impact pattern is reported in the Journal of Applied Physiology in the article, “Are running speeds maximized with simple-spring stance mechanics?” It appears online at http://bit.ly/1Be92Mk in advance of appearing in the print journal.

The finding that faster athletes deliver a firm, rapid punch to the ground upon contact is reported in The Journal of Experimental Biology, in the article “Foot speed, foot-strike and footwear: linking gait mechanics and running ground reaction forces.” It appears online at http://bit.ly/1uskM9v.

Studies compared data from competitive sprinters to other athletes
The tests conducted at SMU’s Locomotor Performance Lab compared competitive sprinters to other fast-running athletes.

The competitive sprinting group included track athletes who specialized in the 100- and 200-meter events. More than half had international experience and had participated in the Olympics and Track and Field World Championships.

They were compared to a group of athletes that included competitive soccer, lacrosse and football players.

All the athletes in both groups had mid- and fore-foot strike patterns. Their running mechanics were tested on a custom, high-speed force treadmill that allowed the researchers to capture and analyze hundreds of footfalls at precisely controlled speeds. Video captured for the studies is posted to the SMU Locomotor Performance Lab Youtube channel. Images on flickr are at http://bit.ly/YKwAtB.

The researchers measured ground-force patterns over a full range of running speeds for each athlete from a jog to top sprinting speed.

“We looked at running speeds ranging from 3 to 11 meters per second,” Clark said. “Earlier studies in the field of biomechanics have examined ground reaction force patterns, but focused primarily on jogging speeds between 3 and 5 meters per second. The differences we found became identifiable largely because of the broad range of speeds we examined and the caliber of the sprinters who participated in the study.”

Classic spring model of running does not explain the unique gait features of top sprinters
The contemporary view of running mechanics has been heavily influenced by the simple spring-mass model, a theory first formulated in the late 1980s. The spring-mass model assumes the legs work essentially like the compression spring of a pogo stick when in contact with the ground.

In this theory, during running at a constant speed on level ground, the body falls down out of the air. Upon landing, the support leg acts like a pogo stick to catch the body and pop it back up in the air for the next step.

It’s been generally assumed that this classic spring model applies to faster running speeds and faster athletes as well as to slower ones.

Elite sprinters do not conform to widely accepted theories of running mechanics
Clark, Ryan and Weyand questioned whether such a passive catch-and-rebound explanation could account for the greater ground forces widely understood as the reason why sprinters achieve faster speeds.

After the researchers gathered ground reaction force waveform data, they found that sprinters differed from other athletes. From there they compared the waveforms to those predicted by the simple spring in the classic model.

“The elite sprinters did not conform to the spring-model predictions,” said Clark. “They deviated a lot, specifically during the first half of the ground-contact phase. Our athlete non-sprinters, on the other hand, conformed fairly closely to the spring-model predictions, even at their top speeds.”

Weyand said the new findings indicate that the classic spring model is not sufficient for understanding the mechanical basis of sprint running performance.

“We found all the fastest athletes applied greater ground forces with a common and apparently characteristic pattern that resulted from the same basic gait features,” he said. “What these sprinters do differently is in their wind up and delivery mechanics. The motion of their limbs in the air is distinct; so even though the duration of their limb-swing phase at top speed does not differ from other runners, the force delivery mechanism differs markedly.”

Sprinters have a common mechanical solution for speed — one that athletes who aren’t as fast do not execute.

“This provides scientific information so coaches and athletes can fully identify what to train,” Clark said. “It is our hope that our results can translate into advances in evidence-based approaches to training speed.”

The research was funded by the U.S. Army Medical Research and Materiel Command and SMU’s Simmons School of Education and Human Development. — Margaret Allen

Follow SMUResearch.com on twitter at @smuresearch.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.