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Sensors Monitor Athletes Inner and Outer Body For Safety
October 2006

Biomechanics innovations ranging from a computer model of a pregnant driver to a head injury monitoring system for the Hokie football team have earned Virginia Tech researcher Stefan Duma a place among the world’s top young technology developers.
Duma, an associate professor of mechanical engineering and founding director of the Virginia Tech-Wake Forest Center for Injury Biomechanics, was named by Technology Review to the 2006 “TR35” roster of the top 35 innovators under the age of 35.

The editors of Technology Review, a publication of the Massachusetts Institute of Technology (MIT) and the oldest technology magazine in existence, selected the TR35 honorees from among hundreds of nominations submitted by universities and industries around the world. Profiles of Duma and the other honorees will appear in the magazine’s September/October edition.

Prof. Duma and the other honorees in the 2006 TR35 class were honored during Technology Review’s Emerging Technologies Conference, recently held at MIT. Speakers included founder and CEO Jeffrey Bezos and AOL chairman and CEO Jonathan Miller.

An alumnus of the University of Tennessee, Prof. Duma completed his first automobile safety project, “An Experimental Study of Airbag Induced Injuries,” in 1996 as his master’s thesis at the University of Cincinnati and realized that the subject of human impact injuries was largely uncharted research territory. Since completing his Ph.D. at the University of Virginia and joining the Virginia Tech mechanical engineering faculty, he has laid the groundwork for a wide range of research.

One of his unique contributions to the field of injury biomechanics is the world’s first computer model of a pregnant driver. His inspiration came in 2001 when was his wife, Christine, was pregnant with their first child.

“If a pregnant driver is in a car accident, there are a number of increased injury risks,” Prof. Duma said. “The risk is primarily fetal mortality.” A study by his research group estimated that about 1,500 fetuses in the second and third trimesters are killed each year in automotive accidents.

Using Christine as the human model, Prof. Duma developed a computer model simulating a uterus and fetus at the seven-and-a-half month stage. The model is being used by automakers to test new restraint designs for pregnant drivers and also can be used to study injuries to pregnant women and fetuses in cases of domestic violence and falls.

Another first is a study of head impact injuries that began during Virginia Tech’s 2003-2004 football season. Working with Dr. Gunnar Brolinson, head football team physician and a professor in the Edward Via Virginia College of Osteopathic Medicine, and Mike Goforth, team trainer with Virginia Tech Sports Medicine, Prof. Duma equips the Hokies’ football helmets with sensors that record impacts in terms of G (gravity) forces. The sensors transmit real-time data to a sideline computer system that keeps track of a range of head impact information for each player wearing the sensors.

Aimed at discovering the levels at which impacts begin to result in concussions and other brain traumas, the study has found that players typically receive 50 to 100 head impacts per game, the most severe equal to the force of car crashes. Coaches and physicians with a number of football teams are using the system for real-time assessments of head impacts. Prof. Duma expects the study to result in designs for safer sports head gear, as well as new concussion treatment and evaluation methods.

The Eye Injury Research Program established by Prof. Duma at Virginia Tech is the nation’s largest research program for airbag-induced eye injuries and one of the largest for all types of eye injuries. His group developed the first computer model of the human eye that can accurately predict the probability of eye injury under any type of impact, as well as the first fluid-filled synthetic eye equipped with sensors to precisely replicate the effects of impacts on the human eye.

In 2005, Prof. Duma received the American Society of Biomechanics (ABS) Young Scientist Award in recognition his research program. This year he is chair of the host committee for the ABS annual conference, which attracted an international gathering of more than 500 researchers to Virginia Tech for the event.

The dangerous heat levels a football player may experience have also prompted sensors to come under study by biological engineering students at the University of Arkansas (UA). They have developed a wireless biosensor that can accurately record and monitor a football player’s body temperature in real time while the player is active. The prototype designed by students in the College of Engineering contributes to research into a commercial product that could prevent death due to heat stroke.

“Deaths due to heat stroke are preventable with new technology,” said Tom Costello, associate professor of biological and agricultural engineering. “Trainers and coaches on the sideline need to know whose body temperature is creeping up there (to a dangerous level). Once you have that information, you can pull the player off the field, hydrate, and give the body a chance to lose some of that heat and cool down.”

For their senior design project, Costello’s students – Matt Graham, John Leach and James McCarty – designed and built a system prototype that, with modifications, could provide potentially life-saving information to coaches and trainers. The system wirelessly gathers and monitors body temperature and communicates information on many players in real time. To the player practicing or participating in a game, the system would be transparent in that it would not compromise safety or affect comfort and performance.

The complete system includes a thermocouple temperature sensor, a transmitter, two amplifiers and a base-station receiver connected to a laptop with user-interface software. As part of the project, Graham, Leach and McCarty exhaustively researched each component to find commercial products that were compatible with each other and most appropriate for their design. For example, they considered many types of sensors – thermistors, infrared sensors and liquid crystal thermometry – before settling on thermocouples, which they found to be superior in response time, size, durability, expense and quality of data produced.

The students embedded the wireless system in a Schutt football helmet, provided by the UA Men’s Athletics Department. The sensor adheres to a dense pad, which touches the surface of the player’s forehead and records the body’s temperature from the temporal artery. The sensor sends an analog signal to the transmitter, which converts the signal into digital data. The amplifiers increase voltage from the sensor to enable it to provide linear, higher-resolution data, allowing the researchers to measure temperature within a tenth of a degree Fahrenheit, the medical industry standard.

The connected components communicate with a base-station receiver, which transfers data into a laptop computer. The system has a transmission distance of approximately 1,000 feet, which would work in the largest football stadiums.

User-friendly software provides basic information that can be viewed in raw form or graphic format. From the software’s main page, each player’s name is a link to a reference page that includes heat stress notes and a history chart. This page also includes buttons that enable the user to set a player’s baseline temperature and changes in threshold temperature. The software allows the user to monitor temperatures of many players simultaneously. Most importantly, based on each player’s threshold, a temperature-alert page automatically pops up and supercedes all other windows if a player has reached his threshold.

Mr. Graham said software changes are easy and could facilitate many types of communication. For example, if a trainer or support person is not available to monitor the software, the alert page could be programmed to sound an alarm, call a cell phone or send a text message.

Supervised by Prof. Costello, the students shepherded their project through many design iterations and rigorously tested the final prototype on subjects in a resting position and during vigorous physical exertion and exercise. In the latter tests, subjects donned the helmet and ran one mile on a level surface in an indoor track facility.

Temperatures gathered by the prototype during the exercise phase were compared to oral, tympanic membrane and temporal artery readings immediately after the subject stopped running. The system recorded accurate temperature readings in real time while subjects were running. The researchers did not test the system’s capability in a helmet-impact environment.

The students won second place at the Open Gunlogson National Student Environmental Design Competition, part of the annual international meeting of the American Society of Agricultural and Biological Engineers. Only the top three teams from schools nationwide were invited to present their designs.

Each year, heat stroke claims the life of at least one high school, collegiate or professional football player. Formal practices hadn’t even begun this year when a 15-year-old student in Rockdale County, Ga., died as a result of heat stroke following a voluntary workout in preparation for the start of the football season. The problem is that coaches, trainers and the players themselves do not know when the body’s core temperature has reached a critical threshold, despite physiological signs such as dizziness and blurred vision.

Heat exhaustion can occur when internal body temperature increases to 100.4 degrees; if it reaches 104.9 degrees, a person may suffer a potentially fatal heat stroke. Football players are especially vulnerable to heat exhaustion and stroke. Their bodies struggle to cool down because they are practicing in temperatures that are as hot or hotter than the body’s temperature. Plus, protective gear, especially helmets – the human body releases 60 percent of its heat though the head – inhibits the body from efficiently releasing heat so it can cool down. ##

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