Time usually heals all surface wounds. However, the underlying muscle that is damaged as a result of the injury may never be the same again, according to results of a new study that suggests therapists should consider new approaches to physical therapy and rehabilitation.

The study, conducted by researchers at the University of Georgia, was published in Scientific Reports.

“Mitochondria is in all of our muscles, and we wanted to know what’s wrong with the mitochondria in injured muscles and if they adapt to exercise,” says assistant professor Jarrod A. Call, a study co-author, in a media release from University of Georgia.

In the study — which also served as a dissertation paper for Call’s former student, Michael Southern, who is now a postdoctoral fellow at the University of Minnesota — researchers in the UGA College of Education examined the mitochondria networks in the cells of injured muscles and compared them with cells in unaltered muscles. They discovered the entire muscle undergoes fundamental changes that affect its long-term performance.

“If you go out and start training for a marathon, your mitochondria will double,” Call adds. “So Michael asked, after a volumetric muscle loss injury, does the mitochondria in the injured muscle grow and expand just like typical muscle mitochondria would?”

The answer, the team found, is no.

Using 3D imaging through a collaboration with the UGA College of Engineering’s Mortensen Lab, the research team saw that not only was the mitochondria network disorganized in the area where the muscle was directly affected by the injury, but the network was affected throughout the entire muscle. Even after a month of exercise, the injured muscle did not regain its health equal to that of typical muscles.

This can have tremendous implications on physical therapy and rehabilitation, where the goal is to bring muscles back to their original, pre-injury condition. The study suggests that simply wouldn’t happen, which means new approaches to rehabilitation should be considered, Call states.

The disorganized state of the mitochondria also could have implications on overall body functions over the long term, Call adds, in the release.

“Typically, with exercise, our muscles would adapt and increase their mitochondrial function. But these muscles would not adapt as well,” Call comments. “So, that fits into one of our sayings in kinesiology — that exercise is medicine. Well, here, exercise is not medicine because it’s not having any effect.”

The study, which was funded by a grant from the Department of Defense to Call and his co-primary investigator, Sarah Greising of the University of Minnesota, will help inform physical therapy and treatment for wounded military personnel with these types of muscle-loss injuries. Call and his team are now beginning to look at further studies involving civilian populations.

“We always like to say that the foundation of rehabilitation is muscle plasticity, which means your muscle adapts. But if your muscle can’t adapt, then any rehab you do to it doesn’t matter,” Call concludes, in the release.

“There seems to be a cellular limitation in the remaining muscle that can negatively impact rehabilitation.”

[Source(s): University of Georgia, Newswise]