Muscle glycogen levels directly impact an athlete’s performance. The standard method to measure muscle glycogen requires an invasive muscle biopsy. The Appalachian State University Human Performance Laboratory at the NC Research Campus has validated a non-invasive ultrasound technology created by MuscleSound® of Denver, Colorado that measures muscle glycogen just as effectively.
Researchers in exercise and sports science can put away their biopsy needles. The Appalachian State University Human Performance Laboratory at the NC Research Campus (NCRC) in Kannapolis validated the use of ultrasound technology to measure muscle glycogen.
Muscle biopsies have been the standard method of measuring muscle glycogen. They involve inserting a needle into a muscle, usually in the leg, to remove a piece for laboratory testing. The procedure can take up to a half-hour, requires a doctor, local anesthesia, stitches, and aftercare that can interfere with athletic training.
Since an athlete’s glycogen level directly impacts their performance, measurement is vital. “When you train intensely, the primary fuel is the glycogen in the muscle and when that is low you cannot push intensely,” explained David Nieman DrPH, FACSM, director of the Human Performance Laboratory and professor of health and exercise science in Appalachian’s College of Health Sciences.
Ultrasound is commonly used in exercise and sports science for real-time visualization of movement and to measure hydration and body fat. MuscleSound® of Denver, Colorado offers a non-invasive portable, diagnostic high-frequency ultrasound and cloud-based software that works by scoring the difference in pixel intensity as muscle scans transition from darker to lighter reflecting glycogen use.
Study Design and Results
To determine the effectiveness of the MuscleSound® system, 20 cyclists allowed ultrasound scans and muscle biopsies of their vastus lateralis muscle, which is part of the thigh, before and after completing a 75 km ride on a CompuTrainer Pro Model 8001. On average, the cyclists experienced a 77 percent decrease in their total glycogen content. Testing prior to the exercise showed whether the athletes had high or low glycogen levels at the beginning of the study. When the ultrasound scans and the analysis of the muscle biopsies were compared, the results correlated closely when measuring both the overall decrease in glycogen and starting and ending glycogen levels. The study “Ultrasonic assessment of exercise-induced change in skeletal muscle glycogen content” was published in the journal BMC Sports Science, Medicine and Rehabilitation in April 2015.
“We couldn’t believe how tight the correlation was,” Nieman noted. “We’re excited about the results because what this does for researchers around the world is that now, without taking a biopsy, we can very precisely measure if athletes are low or high in glycogen.”
The technology is useful for researchers and athletic trainers. “Glycogen has to be supported through a high carbohydrate diet,” Nieman said. “The tendency in some athletes is to eat a lot of meat and dairy products and to avoid foods like fruits, pastas and rice. The high protein diet is not the friend of a high performing athlete. It just won’t get them where they need to be.”
With this technology, trainers can help athletes enhance their performance through a diet designed to keep their muscle glycogen optimized.
By reducing the need for muscle biopsies, Nieman expects to see more research on muscle groups like the deltoids in the shoulder that have not been studied as intensely as leg muscles. He is already using MuscleSound® to provide diet counseling to runners at UNC Charlotte, and is planning a study in partnership with Amy Knab, PhD, professor of exercise and sports science at Queens University of Charlotte, using the system with elite swimmers.
“This is really an honor for us. MuscleSound® looked at all of the labs that could do this testing for them, and they came to us here at the NCRC,” Nieman said. “The NCRC is all about industry and university research, and this is a great example.”
“Our participation in this study is a positive step forward in the complete understanding and optimization of glycogen within the human body,” added Stephen Kurtz, CEO of MuscleSound. “We are proud to be leaders in helping prevent injuries, improve performance and enhance nutrition. Working with App State, Dr. Nieman and his colleagues was an outstanding experience.”