This Is How ‘Muscle Memory’ Can Help Us Stay Fit

Help Us Stay Fit

It may never be too late to start building muscle memories, even if you’ve rarely or never lifted weights.

After two years of COVID-19 and its disruptions to our exercise routines, many of us may feel like we’ve forgotten how to get fit, but an encouraging new study suggests our muscles have memory. The study was carried out on mice but is based on similar experiments with people and weight training. This revealed that muscles developed a long-lasting, generalized molecular ‘memory’ of past endurance exercise that helped them recover quickly from long pauses.

In the study, animals that finished a rodent resistance training routine developed changes in their muscle DNA that lasted long after they stopped exercising. The mice gained muscle mass much faster than other animals when they returned to exercise. On an encouraging note for newcomers to weight training, the results also suggest that we should be able to generate new muscle memories regardless of our age.

Until recently, the term “muscle memory” used to describe our ability to ride a bike, ski, throw to first base, or repeat other common physical tasks, even if we hadn’t cycled, skied, or thrown a baseball in years. Our body remembers how to do it, but this type of memory, while real, is not real muscle memory. These memories exist within the motor neurons of our brain.

However, scientists knew that something happened within the muscles themselves when they exercised, especially during weight training, and that these changes influenced how the muscles responded to exercise afterward. “Anecdotally, people say things like, ‘I used to be an athlete, then I took some time off, but my muscles came back as soon as I started,'” to lift weights again, said Kevin Murach, a professor of health and human performance at the University of Arkansas, who supervised the new study.

Those stories piqued his interest and that of other researchers. They wondered how muscles “remember” previous workouts, and how those memories help muscles recover after time away from the gym.

Muscle Memory

Some preliminary animal studies suggested that genes within the nuclei of muscle fibers functioned differently after resistance exercise. Then, in 2018 and 2019, several highly debated studies involving people looked at the epigenetics of resistance training. Epigenetics refers to changes in how genes work, even though the gene itself does not change. For the most part, it’s a process called methylation, in which groups of atoms, called methyl groups, stick to the outside of genes like tiny barnacles, making the genes more or less likely to turn on and make certain things. proteins.

In recent human experiments, resistance exercise changed the methylation patterns of a number of genes in people’s muscles , and those changes were still evident weeks or months later, even after the volunteers stopped exercising and they lost some of their muscle mass. The researchers found that when they started lifting weights again, they regained muscle much faster than when the studies began. In short, his muscles remembered how to bulk up.

However, those studies, while intriguing, lasted a few months at most. It was not yet clear whether exercise performed long before would linger as genetic memory in our muscles, or how many different cells and genes in the muscles would be affected at the epigenetic level by resistance training.

So for the new study, published recently in Function, a flagship journal of the American Physiological Society, Murach and his colleagues, including lead author Yuan Wen, decided to recreate weight-training experiments in humans as accurately as possible in adult mice. The life of rodents is much more condensed than ours, which means that the changes observed in animals after several months could appear in people after several years.

But since the mice can’t use weights, the scientists made them run on weighted wheels, designed to train the endurance of the leg muscles. The animals trained for eight weeks and then sat in their cages for 12 weeks, about 10 percent of their lives, which to us would be years. The animals then retrained for a month, along with age-matched mice that were just starting to exercise, and served as a control group. Throughout the entire process, the researchers did biopsies and microscopic studies of his muscles.

They observed abundant differences in gene methylation in muscle fibers after the mice trained; most of the changes were maintained months after they stopped exercising. In general, these epigenetic changes increased the function of genes involved in muscle growth and reduced the activity of other genes, making the genetic process of building muscle “more refined,” according to Murach. Even after months of inactivity, these changes helped the trained mice gain more muscle more quickly during retraining, compared to previously untrained mice.

Of course, this study involved mice, not people. In addition, only resistance exercises and not aerobics have been taken into account.

However, since many of the genes the researchers monitored are the same ones the researchers studied in human experiments, the findings are likely to have relevance for anyone who intends to increase their muscle mass in 2022. The researchers suggest the following:

— No matter how long it’s been since we last went to the gym or signed up for bodyweight training online, our muscles should still be primed to respond to exercises when we start training again.

It may never be too late to start building muscle memories, even if you’ve rarely or never lifted weights. All the mice in the study were adults when they started exercising on the weighted wheels, but all managed to create muscle memories that allowed them to bulk up more quickly after a period of inactivity. “It’s better to start at some point than not at all,” Murach concluded.