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Professor will use fiber optics to study muscle-tendon mechanics in jumping

BOONE—The edge. It’s the competitive advantage every athletic seeks, whether it’s seconds shaved off a 100-meter sprint or the extra inches gained when spiking a volleyball or at tip-off in a basketball game.

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Dr. Jeffrey McBride is turning to fiber optics and specialized equipment to better understand the muscle and tendon length changes that occur during jumping and how those changes affect athletic performance.

A professor in the Department of Health, Leisure and Exercise Science in Appalachian State University’s College of Health Sciences, McBride has received a $25,000 senior investigator grant from the National Strength and Conditioning Association.

“My research interest is athlete performance primarily in jumping and running,” McBride said. “Muscles and tendons perform differently in better athletes than average jumpers but researchers don’t know why.”

He will use measurements collected through a series of vertical jumps performed by research volunteers to try and understand how athletes can train to perform better.

Using a surgical needle, McBride will insert an optic fiber no bigger than a strand of sewing thread through the patellar tendon of research volunteers. He learned the technique while a post-doctoral student in Finland.

Light will travel from a transmitter through the optic fiber in the tendon to a receiver. The fiber optics will allow him and a team of graduate and undergraduate assistants to measure the force the tendons exert during a jump.

“When the tendon is placed under force through jumping, for example, it squeezes and cuts the light signal traveling through the fiber,” McBride explained. “We can correlate the amount of light that’s cut to a force value. The more light that is cut off, the more force is being placed on the tendon.”

That information will help McBride and other researchers better understand how much tendon force is associated with different exercises.

When a person prepares to jump, the muscles and tendons lengthen and act like a spring, McBride explained. “When you go down, the tendons lengthen and can store energy like a rubber band. When you let go, the tendon snaps back,” he said. That springing motion is called stored elastic energy, which is more economical in tendons than the energy that’s generated through muscle contractions.

Better jumpers have different changes occurring in their muscles and tendons than what occurs in someone who isn’t as good a jumper.

“We don’t know much about what exactly those changes are,” McBride said. “If we can understand what is happening in the tendons and muscles in the better jumpers, then we may be able to correlate that to ways to better train athletes to improve their vertical jumping ability.”

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