A study from researchers in Finland shows that people can take more than two months off from the gym and quickly regain their strength when they get back to it. Scientists cite muscle memory.
AILSA CHANG, HOST:
As we move from Thanksgiving into the busy winter holidays – let’s be real – it can be really easy to let your exercise routine slide, right? So for those of us who take some time off from working out, here’s some good news – research shows that your muscles will remember. NPR’s Will Stone explains.
WILL STONE, BYLINE: That first time back in the gym can be rough, discouraging. That was true even for a competitive bodybuilder like Eeli Halonen.
EELI HALONEN: So I wasn’t training that much. I lost some – quite a bit of muscle mass.
STONE: Halonen is pursuing a Ph.D. in exercise physiology at the University of Jyvaskyla in Finland. So he knew about the research showing that when you take a break, it’s easier to gain back muscle the second time around. Still, he was surprised at the pace of his own progress after taking a string of months off.
HALONEN: Pretty fascinating to see myself that, OK, this actually happens. And I want to know more about this.
STONE: So he ran a study. People with no training experience worked out several times a week, doing standard exercises like bicep curls and leg presses. Everyone trained for a total of 20 weeks, but one group did it continuously while the other split it up. They took a 10-week break in the middle. Halonen says when that group came back to the gym after their time off, they had clearly lost strength and muscle.
HALONEN: What we found at only, like, five weeks of retraining – so when they resumed, that training was enough to, like, get back where they were.
STONE: In other words, it did not take long to make up those previous gains. And by the end of the study, when you looked at both groups…
HALONEN: There was no difference between the groups in muscle strength or muscle size.
STONE: Halonen’s research was published in October in the Scandinavian Journal of Medicine & Science in Sports. His team is now looking at muscle biopsies to understand why this happened. But scientists already have an idea. It’s a phenomenon known as muscle memory – a term that most of us associate with the phrase, it’s like riding a bike.
KEVIN MURACH: There is this kind of brain-muscle connection that could be optimized.
STONE: Kevin Murach is a professor of exercise science at the University of Arkansas.
MURACH: That’s, like, considered to be, like, kind of a neural patterning and neuromuscular phenomenon. And that sort of thing can also happen with exercise, with training.
STONE: But Murach says there’s more to this idea of muscle memory. Scientists have realized that certain changes inside the muscle cells may explain why a previously trained muscle can grow back quickly.
MURACH: It’s still very much kind of a burgeoning field. It’s definitely, I think, still pretty wide open.
STONE: One leading theory has to do with the nucleus. Unlike most of our cells, our skeletal muscle cells have more than one. These threadlike fibers can have hundreds of nuclei. You add more as your muscles grow. And even if you stop training and your muscles shrink…
MURACH: Those nuclei you added in would remain. They wouldn’t go away. So when you start training again, you can just quickly activate all the things that need to happen for the muscle to grow.
STONE: Another line of evidence from Murach’s lab and others points to changes in the DNA – that certain genes get turned on and off more readily because you’ve trained the muscles once before. Kristoffer Toldnes Cumming is an exercise physiologist at Ostfold University College. Here’s how he sums up muscle memory.
KRISTOFFER TOLDNES CUMMING: It’s like a cellular memory in your muscles that remembers past – we love to use the word glory.
STONE: He agrees the underlying reason for that return to glory is still unclear. It’s hard to do this research in humans, after all. But the takeaway here is straightforward.
CUMMING: A lot of people are kind of stressing out when they lose one training. It’s like the world has collapsed. Relax. Just relax. Enjoy life.
STONE: And as this latest research shows, that’s true, even if it’s been several months since you lifted weights.
Will Stone, NPR News.
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