MRI identifies nerves capable of 'rescuing' muscle fibers

Muscle loss and frailty are unfortunate realities for individuals who reach advanced ages. A study recently published online in The Journal of Physiology may increase clinical interest in developing methods to reverse muscle frailty and disability caused by old age.

According to a press release from the Physiological Society, individuals who reach the age of 75 have 30 to 50 percent fewer active nerves in their legs, which can result in muscles becoming functionally useless. But healthy muscles may stand a chance.  

Researchers from the Manchester Metropolitan University and the University of Manchester in the U.K. with the University of Waterloo in Ontario, Canada, found that adults with large, healthy muscles have their own form of protection that enables surviving nerves to potentially rescue some detached muscle fibers, researchers wrote. The team used MRI technology and enhanced electromyography to analyze and record electrical activity passing through human muscle. Researchers then estimated the numbers and the size of surviving nerves that could rescue muscle fibers. 

Researchers are currently working towards identifying the best strength training or endurance excise and understand the physiology of why nerve-muscle changes occur when people get older, according to the press release. Ultimately, these study findings have given researchers motivation to either slow old-age muscle weakness or increase nerve branching to rescue detached muscle fibers.

"Our research helps to explain why muscles decline with advancing age and this new knowledge will help in the search for effective countermeasures," said senior author Jamie McPhee, PhD, in a prepared statement. "Our challenge now is to find ways to increase the success of nerve branching to rescue detached muscle fibers and thereby reduce the numbers of older people in our neighborhoods with low muscle mass and muscle weakness."