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UNF researcher bent on preventing knee pain



Anyone who’s experienced “runner’s knee” knows it’s a painful and debilitating condition that greatly impacts day-to-day physical activities. This chronic condition characterized by sharp or radiating pain around the kneecap afflicts millions of people, from marathon runners and martial artists to high school students and housewives.

Research shows that 15 to 33 percent of active adults and 21 to 45 percent of adolescents suffer from runner’s knee; those who do a lot of knee-bending activities — walking, biking, squatting or jumping — are more prone to be affected; and females tend to develop the condition more often than males. Despite the high prevalence of runner’s knee, until recently, little research has been done to pinpoint its exact causes or how to prevent it.

Dr. Michelle Boling, assistant professor of Clinical & Applied Movement Sciences at UNF, has spent several years researching this musculoskeletal disorder, also known as patellofemoral pain syndrome, or PFPS. The purpose of Boling’s ongoing research, conducted by observing and collecting motion-analysis data on thousands of physically active people in controlled settings, is to determine the risk factors for developing PFPS and the role gender plays in the prevalence and incidence of the condition. Another intended outcome is to identify injury-prevention techniques to help healthy people avoid developing PFPS and reduce additional potential health problems that typically follow the disorder.


“My research involves looking at risk factors for patellofemoral pain, which is one of the most common chronic knee injuries in runners and those we call ‘weekend warriors,’” Boling said. “It develops over a period of time, and those who seek rehab for it typically don’t ever get 100 percent better, so they end up self-selecting themselves out of being physically active. This leads to a whole cascade of problems later in life [including obesity, diabetes, hypertension and osteoarthritis] so we really want to prevent PFPS early on.”


Boling was part of a team of researchers that, in 2005, began to collect baseline data and assessed the ongoing knee health of nearly 1,600 midshipmen enrolled at the United States Naval Academy in Annapolis, Md. Boling said there were several advantages to selecting this particular population: Researchers could assess the participants’ health as they entered the academy as freshmen, including only those with healthy knees at the onset of the study; all participants would be required to take part in the same regular, strenuous physical activity as part of their training program; both men and women would be studied; and the subjects’ medical records would be easily accessible.

Baseline data collected included 3-D motion analysis during jump landings and lower-extremity isometric strength tests and body alignment measurements relating to the participants’ navicular drop (mid-foot/arch alignment) and Q angle (the angle between the thigh muscles and the tendons of the knee). The researchers looked at hip-rotation angles and strength of the muscles in the lower extremities, as well as overall body mechanics during various movements. All of these measurements were recorded to use later as a comparison/reference when the inevitable knee injuries started happening.

“What we do is test healthy people and then we follow them throughout their four years at the academy as they’re physically active to see who develops PFPS,” Boling said. “For those who develop it, we go back and see how they were different from those who stayed healthy and didn’t develop an injury.”

As expected, a number of participants in the initial study were later diagnosed with PFPS — 24 women and 16 men, according to medical records — and the team set to work analyzing data, formulating hypotheses and determining risk factors.

“We now know that people with weak thigh musculature, the quadriceps and hamstrings, are four to five times more likely to develop patellofemoral pain,” Boling said. “We also found that people with fallen arches, a measure of navicular drop, have 3.4 times greater risk of developing patellofemoral pain syndrome compared to those without fallen arches, and individuals who had more internal collapse of the femur, were about 1.5 times more likely to develop the condition.”

It might sound like a bunch of mumbo jumbo to some, but this is the kind of information scientists can use to develop PFPS prevention techniques to share with athletic trainers and coaches working with athletes.

Boling and her colleagues at the University of North Carolina at Chapel Hill, College of Charleston, Uniformed Services University and the United States Military Academy now have plans to expand their research base, thanks to a $145,000 National Institutes of Health grant she received in June. The grant will allow the research team to nearly quadruple the number of participants in similar studies over the next two years at additional facilities.


“This grant will allow us to expand to West Point [military academy] and the Air Force Academy, so it gives us a little more power to say these definitely are the risk factors that we’re seeing in individuals,” Boling said. “But it will also allow us to analyze more specifically by gender, giving us enough power statistically to pull out data from females alone and males alone to investigate their gender-related risk factors.”

Dr. Darin Padua, exercise and sport science professor and director of the Sports Medicine Research Laboratory at UNC, has worked with Boling since 2001 in various capacities and now serves as a consultant for her current work.

“Michelle’s research investigating risk factors for chronic knee pain in people who are physically active can ultimately provide important information that helps us to keep people physically active for long periods without experiencing negative side effects,” Padua said. “As a result, this has huge positive impacts on the overall health and well-being of our society.”

Boling also has worked with 150 Northeast Florida high school student-athletes the last two summers to look at the same type of data as it relates to adolescents. “We linked up with the Brooks Center for Sports Therapy because they already had relationships with Nease High School and Ponte Vedra High School in St. Johns County,” Boling said. “We’ve been able to go out and collect some preliminary data and try to develop relationships with the schools’ athletic trainers and team physicians to see if the risk factors in a younger population are the same as what we see in older, collegiate populations.”


The research team works with students who receive sports physicals at their schools in the summers, conducting similar baseline tests as the military cohort. Plans are also under way to expand the research to include student-athletes from Bishop Kenny High School in Jacksonville.

Emily Hartley, a former UNF undergraduate student and current graduate assistant athletic trainer at University of Kentucky Sports Medicine, worked with Boling on similar research her senior year at UNF. “If there is an efficient way to screen for [PFPS] factors during pre-participation physical exams, we may be able to prevent these injuries,” she said.


Boling said she’s focused on moving more toward prevention rather than rehab following injury. “We’re trying to develop simple worksheets we can share with coaches and athletic trainers to explain the movement patterns they may want to look at to avoid injuries in the future. If we can prevent injuries before they happen, that’s a very good thing.”