Most of us have experienced muscle memory, the neuromuscular ability that helps us confidently ride a bike or swing a tennis racket — even if we haven’t done those activities for years.
Recent research suggests that muscle memory may also explain how previously trained muscles can rapidly regain their size and strength after months without lifting.
Surprised at how quickly his own muscles recovered after an extended break from training, Eeli Halonen, a doctoral student in exercise physiology at Finland’s University of Jyväskylä, assembled a research team. They recruited 55 people with no weightlifting experience and led them through a 20-week workout program. About half of the participants took a 10-week break midway through the program before resuming their workouts for another 10 weeks.
When they measured the participants’ muscles during the break, researchers found they had decreased in size and strength. Once back in the gym, however, these individuals regained their lost muscle mass in a mere five weeks.
Scientists are still trying to understand rapid muscle regeneration. One theory posits that the nuclei in skeletal muscle cells remain even as muscle fibers shrink, poised to reactivate when called upon. Another theory suggests that strength training rewires the muscles’ DNA, allowing certain genes to switch on more readily when workouts resume.
“It’s a positive finding for those [who] need to take time off for whatever reason,” notes Kevin Murach, PhD, a professor of exercise science at the University of Arkansas, in an interview with NPR. “You can rest assured that your muscles will readapt quite readily.”
This article originally appeared as “How Muscles Remember — and Regain Lost Strength” in the July/August 2025 issue of Experience Life.
Comments (0)