Chancey Unravels Mechanics of Neck Muscles



By Claire Cusick, September 2004



Carol ChanceyEven though Carol Chancey’s field is called biomechanics, it’s the mechanics that came first for her.

"I’m a traditional mechanical engineer by training," she said, complete with a bachelor’s and master’s degree in the field from Auburn University.

Like many engineers, Carol has always been fascinated by how things work. Growing up on a farm in Ozark, Ala., meant a childhood spent around large machinery that inevitably needed fixing. She watched both her father and grandfather work to maintain their equipment and eventually learned to help.

"You become a self-taught mechanic," she said of the typical farmer. Every farmer wants to at least attempt to fix whatever’s broken before calling someone who will need to be paid. In addition, her dad owned a T.V. and radio repair business for many years.

"My dad can repair just about everything," Carol said. "I always loved helping him.”

The other childhood factor that steered Carol toward engineering was her many trips to Disney World.

"I was three when I first went to Disney World. I got hooked on Disney magic and how Disney magic was possible: how the rides worked, how the different worlds were created, how the Bear Jamboree bears could sing and dance, how the car went through water in Pirates of the Caribbean – my favorite ride," she said. "It all made me want to know more about how things worked and how motion was possible.”

Carol went off to study engineering at Auburn, just two hours away. In addition to her engineering work, she also picked up another bachelor’s degree in applied math.

"I love math and all sciences. I could have gotten a degree in any of them," she said. "My math professor in my freshman calculus class encouraged me to get a degree in math. It’s amazing how many times my fellow Ph.D. engineering graduate students tell me they wish they had had more math. I cannot adequately describe how valuable those experiences have been!”

While still an undergraduate, Carol began to seek out opportunities for internships and summer work.

As it happens, the U.S. Army Aeromedical Research Laboratory (USAARL) at Ft. Rucker is located near her hometown of Ozark, Ala. Ft. Rucker is the army’s primary helicopter pilot training base, and the agency conducts biomechanics research on pilot protective equipment and restraint systems. She worked there for three summers, as well as during holidays and breaks. She has designed equipment, evaluated protocol and algorithms, and functioned as an on-site experimenter, trainer and data analyst for many research projects for the U.S. Dept. of Defense, U.S. Navy, and U.S. Army, including the Navy-funded "Amelia"project, which studied safety equipment compatibility for female naval aviators.

It was there that she realized she enjoyed the "helping people" element of engineering much more than just isolated mechanics work. Even though a good rotor means a good pump and efficiently pumped water -- which is a good thing -- she wanted her work to have a more direct impact on people.

"I wanted to cut out the middle man, so to speak,"she said, "and do work that would directly impact individuals."That’s when she began to consider biomechanics.

One of her mentors at Ft. Rucker had earned his Ph.D. under the supervision of Jim McElhaney, former Duke Department of Biomedical Engineering chairman. McElhaney is considered a leader in the field of injury biomechanics, Carol said. By 1997, when Carol was considering her options for grad school, another of McElhaney’s Ph.D. graduates, Dr. Barry Myers, had taken over his lab. So with that connection to McElhaney and the prominence of Duke’s head-and-neck lab, Duke was high on her list of places to consider for her doctorate, and those connections ended up being the reason she came here. She arrived in Durham for the fall of 1998.

"Actually, one of the reasons I came here is to learn biology," she said.

Carol now models neck muscles. She has done a lot of experimental work, a lot of basic science, research to improve understanding of the mechanical properties of the neck.

She’s been doing tension testing to help prevent air bag injuries. "Tension" in this case has a specific meaning: it causes the head to be pulled or otherwise moved away from the body, elongating or stretching. She studies the muscle structure and action that allows the movement. She also studies what causes "failure."Failure occurs when someone breaks their neck.

The main discovery she’s made is to simulate a muscle response for the relaxed individual (the person who doesn’t know an accident is about to happen) and the tensed individual (the person who sees an accident happening and braces for it). That’s the first time that’s been done, she said.

Prior to her work, all computer models allowed behavior that equaled a baby’s – young infants who haven’t learned to hold their heads up yet.

But she’s been able to get a better idea of "tolerance"– the level at which an injury would occur. All of this means better standards for the automotive industry, dictated and enforced by the National Highway Transportation Safety Administration (NHTSA), who funded the work.

"They can use the models with their crash testing," she said. In the summer of 2004, she traveled to Washington, D.C. to confer with NHTSA about their next generation of crash-test dummies. Her models help dictate how to make the dummies.

"I really did remove the middle man," she said.

In addition to her research, Carol keeps busy outside of the lab. On campus, she’s held positions in the Graduate and Professional Student Council (GPSC), served on Duke University's Board of Trustees Standing Committees, and currently chairs the programming committee for Duke’s Women in Science and Engineering (WiSE) program. She also enjoys volunteering at local elementary schools and museums, where she can share her love of science and engineering.

"That’s the other reason I came to Duke," Carol said. "Graduate students can be involved in activities outside of the lab and be a part of the university and the community.”