January 13, 2025 | Erin Bluvas, bluvase@sc.edu

What do Mark Wahlberg and the Arnold School’s newest exercise science assistant professor, Sten Stray-Gundersen, have in common? A passion for blood flow restriction training. The celebrity/fitness fanatic uses it as part of his carefully curated workout routine. Stray-Gundersen meets it at the molecular level.

Though the technique first became popular among body builders and martial artists in the 70s and 80s, the clinical use and scientific research surrounding its benefits for rehabilitation, performance and overall health is much more recent. Stray-Gundersen is already a well-known name in the field because of his late father, Jim, who pioneered the “live high train low” high-altitude training paradigm used by elite athletes around the world. He then discovered blood flow restriction training as it was making its way to the West, identified its safety and efficacy considerations and subsequently launched a company (B Strong) aimed at making the approach available to the masses.

Stray-Gundersen hasn’t just followed in his father’s footsteps, he’s propelling the field forward. His passion for the science of blood flow restriction and cardiovascular physiology began with conversations around the dinner table, but an injury that ended his soccer career made it even more personal.

“Experiencing blood flow restriction as a rehabilitation technique really sparked my interest in the underlying physiology of this process and how the body responds to various stressors,” Stray-Gundersen says.   

With his athletic career at an end and inspired by his dad’s work in this area, he decided to pursue graduate degrees in the field. A native of Dallas, Stray-Gundersen returned to his home state to study exercise physiology at the University of Texas at Austin.

During his master’s and doctoral programs, he built on his biology degree and collegiate athlete experiences from Dartmouth College. His time attempting to play in the pro leagues emphasized the importance of exercise physiology even more.

“During graduate school, I was able to contribute to an area of research that was just beginning to emerge,” Stray-Gundersen says. “We were learning how restricting blood flow – by using pressurized bands on the arms or legs – can heal and enhance the body by simulating high-intensity exercise using low intensities and/or loads essentially giving it the benefits of high-intensity exercise without some of the potential drawbacks of traditional strength training, particularly in populations that may have an increased risk of injury.”

Some of the earliest clinical uses of this approach include sport rehabilitation with physical therapists and athletic trainers like Stray-Gundersen experienced firsthand. Since then, scientists have expanded its applications to other contexts, such as military, emergency services and other high-stress/performance occupations.

It can even optimize physical activity for the broader population by prompting adaptations in the body that may be more effective and efficient than existing methods. In other words, "a better bang for your training buck," as touted in scientific circles and by exercise enthusiasts.

As Stray-Gundersen entered his doctoral program, he picked up a second area of specialization: intermittent hypoxia. Though a very different therapy, this restriction of oxygen also holds promise in helping individuals improve their cardiovascular function and glucose control and may even increase their ability to learn new skills.

After graduating in 2023, Stray-Gundersen joined the Arnold School as a postdoctoral fellow in Shawn Arent’s Sport Science Lab. He had been following the exercise science chair’s performance research in military and sports populations for years and was ecstatic at the opportunity to work for him in the renowned exercise science department.

“USC, the Arnold School and the exercise science department offer some of the best support and resources in the world for this type of research,” says Stray-Gundersen, who took on the title of assistant professor this semester. “I knew it would be the perfect place to continue my training and then to lead my own lines of research with incredible mentorship.”

"Sten brings such a unique background to our department because he has been immersed in the field of human performance his whole life. It’s literally a part of who he is," says Arent. "On top of that, his pure enthusiasm for our work is contagious. His skillset and interests will help elevate our research as well as the experiences for our students. I believe he will be a real asset to our department and the school from both a personal and professional perspective."

Today, Stray-Gundersen's research investigates blood flow restriction and intermittent hypoxia – both separately and together, as combining these treatments may offer the most efficient and robust responses for certain populations. His dad remains integral to his journey and always will.

“My dad is a fundamental part of why I chose this profession,” Stray-Gundersen says. “My big life purpose is to carry on his legacy in research and beyond.”