Muscle Research Is Going Strong
In October of 2016, the Centers for Disease Control and Prevention (CDC) officially recognized sarcopenia, or the age-related loss of muscle mass and strength, as a diagnosable medical condition. Now, as older adults begin to receive this diagnosis, physicians will be looking for reliable treatments to improve muscle strength for their patients. Thankfully, Dr. Joni Mettler, associate professor in the Health and Human Performance Department, has been researching one such treatment — neuromuscular electrical stimulation — since she began at Texas State six years ago.
At Texas State, Mettler is the director of the Translational Neuromuscular Physiology Laboratory, based in the Jowers Center. Mettler first became interested in the effects of inactivity on muscle mass and function during her post-doctoral fellowship with the University of Texas Medical Branch in Galveston. During her fellowship, she spent a great deal of time working with the bedrest model, which looked at muscle wasting and changes in muscle function after extended periods of inactivity. This experience, coupled with her experience in athletic training, led her to focus her research on neuromuscular electrical stimulation (NMES) as a possible treatment for muscle wasting.
NMES is a treatment used by athletic trainers and physical therapists to induce muscle growth and strengthening and is conducted by placing electrode pads over the muscles and providing electrical current, which causes the muscles to artificially contract. While this treatment is used frequently in physical rehabilitation, Mettler points out that “the research evidence isn’t clear regarding its effectiveness.” Her research aims to get answers about the treatment’s effectiveness, not only for the aging population and individuals with neurological conditions, but also for young people, such as athletes, who would benefit from NMES as a possible alternative to resistance training exercise. Having an alternative treatment option would be beneficial in cases when regular exercise or resistance training may be difficult or unsafe for the individual to perform.
When Mettler began her first NMES study at the university, she was among very few scholars globally who were looking at the effects of this treatment at a cellular level in human muscle. Her first project was funded by a Research Enhancement Program grant, an internal funding opportunity for Texas State professors. The study examined the effects of NMES on muscle anabolic response (growth) in stroke patients in comparison to healthy older adults. In this study, Mettler found that a one-time NMES treatment did, in fact, increase cellular factors that regulate muscle growth in both groups. Notably, although the stroke patients displayed an impairment in physical function compared to the healthy adults, there was no difference in the effectiveness of the NMES between the two groups.
"My passion and my goal is to try to help reduce the effects of sarcopenia and muscle wasting so that people can continue to live active lives and take care of themselves as long as possible."
-Dr. Joni Mettler, Associate Professor
Next, Mettler received funding from the National Athletic Trainers’ Association Research and Education Foundation to study NMES in young healthy adults. This time, Mettler wanted to answer the question of whether the frequency of the electrical current delivered to the muscle influenced muscle growth. At the end of the study, she found that both a low and high frequency of NMES induced anabolic signaling that leads to muscle growth, but this signaling was elevated to a greater degree with the high frequency treatment. Knowing that different frequencies produce varying results benefits physical rehabilitation professionals working to deliver the most effective NMES regimens for clients who may want to train a muscle toward a specific adaptation.
This spring, Mettler began her third NMES study, which examines the extended effects of NMES in healthy older adults. In this study, she will deliver the NMES treatment to participants’ legs three times a week over a period of four weeks, after which she will measure changes in muscle function, as well as participants’ self-efficacy of physical activity. Ultimately, she hopes to answer the question: do people perform more physical activity after receiving NMES? The answer to this question will help to determine if NMES is an effective treatment for sarcopenia, the effects of which Mettler hopes to remedy. “My passion and my goal is to try to help reduce the effects of sarcopenia and muscle wasting so that people can continue to live active lives and take care of themselves as long as possible,” she shares. Sarcopenia is an important issue to Mettler, who says that mobility loss is a health concern that spans beyond transitioning to a wheelchair. She explains that “once you’re confined to a wheelchair, then a host of other problems start to happen, like insulin resistance (which leads to diabetes), high blood pressure, heart disease, obesity, etc.” With the help of NMES, Mettler hopes to keep people walking and out of a wheelchair when possible.
Because Mettler knows that laboratory research can seem far-removed for some, she stresses the importance of the word translational in her lab’s name. Her mission is to translate the basic science behind her research into clinical practices that influence everyday people, especially those in the aging population who are experiencing mobility loss. Thankfully for those people, Mettler’s research won’t be slowing down any time soon.