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Research / Discovery

Health and Exercise Science professor strengthens understanding of muscle fatigue

June 7, 2013

Rudroff study found that PET imaging is much better suited than EMG to detect activity across individual muscles during fatiguing tasks.

Despite massive strides in technology, researchers' abilities to investigate muscle fatigue with non-invasive techniques such as electromyography can have a lot of limitations. EMG is used to measure the electrical impulses of muscles during contractions, but only measures activity in a very small portion of a muscle. This makes EMG an ineffective technique for obese persons, who may benefit most from muscle-fatigue research.

A creative researcher who recently joined the faculty at CSU, however, has muscled up an innovative strategy to overcome these limitations.

Department of Health and Exercise Science Professor Thorsten Rudroff recently published a study that compared EMG with Positron Emission Tomography, or PET, in order to measure glucose uptake in skeletal muscles during fatiguing contractions in younger and older men. He found that PET imaging is much better suited to detect muscle activity across individual muscles during fatiguing tasks.

His research will provide the information necessary to develop appropriate interventions for older adults and those with diseases such as multiple sclerosis and diabetes.

"I'm interested in muscle fatigue, what's going on in the muscles during fatigue tasks, in the healthy, the young and old," Rudroff said.

Blood flow, glucose uptake during contractions

More specifically, Rudroff is interested in the blood flow and glucose uptake in muscles during fatiguing contractions, for which PET scans are particularly effective.

"Muscles, when they work or do contractions, they use energy," Rudroff said, adding that this correlates to increased glucose activity. "We can see that older men, for example, use much more glucose to accomplish the same fatigue tasks as young men."

PET scans are crucial because they allow Rudroff to see something specific in the body. Rather than only quantifying blood flow in the whole leg, he can focus on a specific muscle or muscular problem, which is significant for patients with MS.

With the information gleaned from these tests, professionals will be able to develop effective interventions, such as different medications and exercise prescriptions for older adults and patients with conditions such as MS.

"The goal is first to understand the mechanism of muscle fatigue, what is going on in the muscle during fatigue and contraction, and then to get useful information for physical therapists to come up with good intervention strategies, ways to design rehabilitation programs and prevention programs, and also, for example, in older adults, to determine which medication would be most useful to influence glucose uptake or increase blood flow to the muscles," Rudroff said.

"We cannot cure MS with this research, but we can increase the quality of life of these patients," Rudroff added. "When we know that muscle energetics are altered or impaired in these patients, we can design more effective rehabilitation programs to improve muscle strength and to provide greater fatigue resistance."

First semester at CSU

This is Rudroff's first semester at CSU; he said this university is "perfect for me."

"CSU has been very helpful with my research," he said. "I have time enough to start with my lab with reduced teaching for the first three years so I can focus on my research, write grants, and publish my scientific results."

Rudroff said what he enjoys most about the Department of Health and Exercise Science is that it is full of opportunities for research collaborations with well-established colleagues, which provides the opportunity to conduct more well-rounded comprehensive research, resulting in more answers to our questions.

Rudroff said he is enjoying his time teaching. "I am impressed by the motivation and quality of students at CSU."

The Department of Health and Exercise Sciences is in the College of Health and Human Sciences at Colorado State University.

Contact: Gretchen Gerding
Phone: 970.491.5182